Tag Archives: space travel

318. Too Many Exoplanets

trappppIt’s official. The good old days are gone.

About a year ago, I said:

(T)he party is nearly over. We now have the capacity to discover extrasolar planets, and new ones are found every year. Fortunately for latecomers to the planet builders guild, megaplanets are easier to find that Earth sized ones, and NASA keeps cutting funding. Still, it won’t be too many years before you can’t decide for yourself where, within the limits of orbital mechanics, you want the planets of Alpha Centauri or Procyon to be.

Science has a way of getting somewhere a lot faster than you would expect. Manned space exploration doesn’t fit that statement, because it runs on politics, not science.

On February 22, in Nature, it was announced that seven Earth size planets had been discovered circling a single star only thirty-nine light years from Earth. Far more important, all seven orbit within the band of temperature where liquid water is a possibility. By contrast, our system has one such planet, Earth, and maybe Mars for a few minutes on a hot afternoon near the equator in mid-summer – if the ice doesn’t sublimate instead. Seven; its unheard of.

The star is TRAPPIST-1, an M dwarf. 

In fact there has been a mini-revolution in the search for exoplanets. NASA’s Kepler space telescope has found more that 4700 potential planets. Many of these will no doubt turn out to be false positives, since the techniques of the search are not perfected, but it is still a staggering number. Most of these were found around stars similar to our sun – where else would you look first? Very few of them are both Earth sized and at the right distance from their star to have the possibility of liquid water.

As I said in Cyan, “planets of no use as real estate.”

Since a mechanical failure in 2013 compromised its ability to orient itself, Kepler has concentrated on observing red dwarfs. To eveyone’s surprise, the planet candidates found around these small, dim stars tend to be more Earth sized. And there are a lot of them.

The TRAPPIST-1 discovery, however, was not by NASA but by the TRAnsiting Planets and Planetesimals Small Telescope group operating out of the University of Liège, Belgium. That explains the use of caps; TRAPPIST is an acronym.

If you want details – and of course you do – the best source is here. This page from the University of Liège is in French, but the video which will self-start is in English, and gives enough details to stir the blood of any space or science fiction fan.

It took me about three seconds to start speculating about what kinds of novels could be written about the exploration of the TRAPPIST-1 system. Suppose most or all of the seven planets had some form of life, all evolving independently. Suppose we write about a paleontological mission on a planet which had vertebral life, then lost it; these dwarfs have a solar wind that operates heavily on planets so close in. Suppose at some time in the deep past, a spacefaring civilization arose on one of these planets, colonized the others, and then died out. Or didn’t die. Or seems to have died until our intrepid explorers begin to poke around.

Okay, I was wrong. The golden age is still here.

202. Planetary Scale

     Everything in a writer’s life is grist for the mill. For a science fiction writer that includes science itself and, in my case, the teaching of science.
     Here is some more teacher geek. In a book on teaching middle school astronomy, this would be an appendix.

When I was in my early teens and discovered the local library, it not only gave me science fiction, but science as well. I remember the dozen or so books on popular astronomy. I particularly remember How to Build a Telescope, which aroused my lust then dumped me when I found out I didn’t have enough money to but the mirror blanks.

The single issue that most challenged the writers of those books was how to convey the scale of things. Now, if you are under forty, you will have to project your mind back to the days when print technology did not include glossy paper and color photography. Visualize a few grainy black and white photos, a few drawings, and lots and lots of words. Like, “If the distance from the Sun to the Earth were equal to the thickness of a sheet of paper, then the distance to Alpha Centauri . . . “

I grew up figuring out that kind of analogy, but if I gave such a book to one of my modern students, their eyes would glaze over and the wheels would stop turning. The children of Sesame Street have to be shown.

Would you like a simple example? Did you know that a softball is moon-size in comparison to a 12 inch classroom globe of the Earth? And if you hold the softball 30 feet away from the globe, it will be proportional in distance as well as size.

For the rest of the solar system, you can’t show both proportional size and proportional distance in a classroom. You can buy a poster with the proportional sizes, but the planets are all on top of each other. If you make a chart of proportional distances, the individual planets will be too small to see.

You can do both, however, if you are willing to take the exercise outside.

We are about to make a model of the solar system. If you want to get out your calculator, be my guest, but I’ve already done the math and I’m willing to share. The scale I used was one to one billion. It would be easier in metrics, but we will eventually be using a local road map for this, so the good ole American system will have to do.

The chart below is in miles and double-steps. That’s because we want your students to get into the act and count the distance to the planets. A double step is normal walking, counting every time your left foot hits the ground, one-and-two-and-three-and . . .

Your sun will be about five feet in diameter. I looked for years for a balloon that size and never found one, so each year I made a new five foot diameter circle of paper and taped it to the outside wall of my classroom. The distances you need are:

Mercury        38 double steps
Venus            71 double steps
Earth             99 double steps
Mars            150 double steps
Jupiter         513 double steps or 0.5 miles
Saturn                                           0.9 miles
Uranus                                         1.7 miles
Neptune                                       2.7 miles
Pluto                                            3.5 miles

You can skip Pluto if you want, but when I first started doing this, it was still a planet.

Give some of your students models of the planets (we’ll talk about sizes below) and take off with the whole class, counting double steps. At 38, leave the student with the Mercury model and continue with the rest of the class. Et cetera.

My double steps go through Jupiter because our playground allowed us to get almost that far. When we reached the boundary fence, I would tell them, “Jupiter is just beyond that house.” Then I would reel off where Saturn through Pluto would be found. My recital would mean nothing to you; you need to make up your own. Find a large scale local map, measure out distances from your classroom, and memorize them. (For us, Pluto was in the next village.)

None of this would be worthwhile without models to show how small our planets are in comparison to the space they inhabit. I made Mercury, Venus, Earth, Mars, and Pluto out of  beads or glass headed pins, stuck into dowels. Be sure to paint the dowels orange for when Johnny loses one in the long grass. The rest of the planets were made of rubber balls found after multiple trips to toy stores, and painted with artists’ acrylics.

You need these sizes, and this time I’m going metric because it’s way easier.

Mercury       5 mm
Venus        12 mm
Earth         13 mm
Mars           7 mm
Jupiter     143 mm
Saturn     121 mm
Uranus      52 mm
Neptune    50 mm
Pluto            3 mm

Feel free to pass this on to anyone who might want to make this model.

187. The Rest of the Landings

Everybody remembers Apollo 11 because it was the first, and Apollo 13 because it failed. And because they made a movie about it. There were five other moon landings.

Apollo 12 — This flight made a precision landing in the Sea of Storms, near the landing place of the Surveyor 3 unmanned probe. Pete Conrad and Alan Bean walked on the moon while Richard Gordon remained in the command module.

Apollo 13 — Once we had reached the moon with Apollo 11 and repeated with Apollo 12, public interest dropped off dramatically. The Apollo 13 flight saw reduced coverage until the explosion. In the movie, Marilyn Lovell says about the newsmen laying siege to her house, “Landing on the moon wasn’t dramatic enough for them – why should not landing on it be?” It is a fitting statement about the last half of the Apollo program.

Apollo 13 suffered a catastrophic explosion and barely got its crew back alive, without landing on the moon. Jim Lovell, Fred Haise and Jack Swigert became part of American myth, especially after the movie Apollo 13.

Apollo 14 — Alan Shepard and Edgar Mitchel piloted their lander to Fra Mauro, the planned destination of Apollo 13. Stuart Roosa was command module pilot.

Apollo 15 — Al Wordon was the command module pilot. David Scott and James Irwin landed on the moon near Hadley rille. This was the first mission to carry a lunar rover, a powered wheeled vehicle that allowed the astronauts to range further from their landing site.

Apollo 16 — Ken Mattingly – who had missed the Apollo 13 mission due to a measles scare – was command module pilot. John Young and Charles Duke landed in the lunar highlands where they collected samples that were geologically older than those brought back by previous missions. Second use of a lunar rover.

Apollo 17 — Ronald Evans was the command module pilot of the last moon mission. Gene Cernan and Harrison Schmitt became the last two men on the moon (so far). They carried the third lunar rover. Schmitt, a geologist, was the only scientist-astronaut to reach the moon.

Apollo 20 was cancelled so its Saturn five booster could be used to launch Skylab. Apollo 18 and 19 were cancelled by budget cuts. All this was done before the launch of Apollo 16, so Cernan, Schmitt, and Evans knew that they would be the last.

For now.

*          *           *

There is one good video of a lunar lander launching from the moon, taken during the last mission. You see a few seconds of it occasionally on PBS space specials. I also found it a this URL: https://www.youtube.com/watch?v=XlGis35Epvs

This appears to be legit, although the things you can find on You-Tube are sometimes outrageously fake. The pictures were taken from a video-camera mounted on the lunar rover, remote controlled from Earth. Similar filming had been attempted on Apollo 15 and 16, without much success.

186. Apollo 11

Apollo 11 was the first moon landing, but Apollo 13 got the movie because of the extra drama. Except for the absent landing, you probably won’t find a better picture of an Apollo mission than that film. This visuals are stunning and the portrayal of events is quite accurate.

Apollo 11, 47 years ago today, was a complete success, but it flirted with disaster twice, in two separate events, minutes apart during the landing. It was broadcast live, so everyone in America and half the rest of the world heard the crises in real time, but you would have needed to be an insider to understand them at the time. I was listening, glued to the TV screen, and I only later realized what was happening right in front of me.

The lunar lander separated from the command module as scheduled. Armstrong and Aldrin fired its rockets to slow its orbit. As it fell toward the moon, there was an alarm – a code 1202 – on the lander’s main computer. Only two men at mission control knew immediately what it meant. The mission was so complex that there were probably thousands of things only a few of those present fully understood.

The computer was overloading. Too many things were happening at once for it to handle. You need to remember the incredibly tiny capacity of 1969 computers. It could not keep up with events, the queue was getting long, so the alarm sounded. Steve Bales recognized that the computer was still doing everything it needed to do, that it would clear the queue in a few seconds, and said GO when most of those present were thinking ABORT. The mission continued, the computer worked through the queue, and then the alarm went off again. Bales said GO. A third time the computer overloaded and Bales shouted GO for the third time just as the lander was approaching touchdown.

The problems weren’t over. The lander had overshot its target and Armstrong found himself over a massive boulder field. There was nowhere to land.

An abort would have meant firing off the upper stage rocket and returning to the command module, allowing the now nearly empty lower section to crash to the moon, and missing the landing. Instead, Armstrong chose to adjust his rate of fall to a near hoover, tilt the entire lander – now top heavy and prone to flipping – to slide sideways and, just as the last of the fuel was nearly gone, reach a clear area where he set the lander down on the lunar surface.

On Earth, we had all been holding our breaths. We just didn’t realize how much reason we had had to worry.

185. The Flying Bedstead

300px-LLRV_2Tomorrow is the anniversary of the Apollo 11 moon landing. For most of the followers of this blog, it is part of history. I saw it happen, on a grainy black and white TV in the lounge of a college dorm. (see 27. That Was My Childhood)

You can’t land on the moon by parachute, nor by wings. No air. The only choice the Apollo program had was to land tail first, by rockets, something that had been a science fiction staple for decades, but was nothing like easy to manage. (see yesterday’s post)

Designing a craft to do the work was within the limits of the technology of the day. Vertical landings on Earth had been successfully accomplished. Pilot control on Apollo was expedited by having the astronauts stand to fly the Lunar Lander; the problem with VTOL planes had been that the pilots were strapped into a seat that kept them facing the wrong way when they landed.

The craft could be built, the astronauts were the best test pilots America had to offer. But how do you train?

Simulators? Maybe. Resurrect Pogo or Vertijet? Perhaps. Build a new craft just to use as a trainer? Better. But how do you build a trainer to react as if it were in a 1/6 gee field while landing in on Earth? You can’t just make gravity go away – or can you.

The answer is almost, more-or-less, and good enough to do the job. The first iteration of the trainer was the Lunar Landing Research Vehicle, nicknamed the flying bedstead. You may have seen it. Neil Armstrong ejected from one of them after the controls failed; the footage of the crash is both exciting and brief, which gets it a lot of air play in retrospective specials, especially on anniversaries like tomorrow.

If you see footage of the LLRV not crashing, or of the advanced version LLTV (Lunar Landing Training Vehicle), you can easily see what it is all about. The vehicle consists of an open framework of tubing with the pilot sitting upright in the front (in an ejection seat, thank goodness) with a batch of somewhat shrouded equipment balancing the rear. In the middle, attached vertically, pointing downward and clearly throwing flames, is a jet engine. The craft is uneasily hovering.

Note, I didn’t say hovering on its jet. That is what it looks like, but that is not what is happening. Not quite. When the jet is fired up at takeoff, the LLRV or LLTV simply sits there. The jet has 5/6 of the thrust needed to lift the craft. While hovering, the rest of the thrust is provided by a separate set of hydrogen peroxide thrusters which are controlled by the pilot. If the pilot were to simply turn off his thrusters, the LLTV would crash to the ground at the same speed it would crash to the moon.

The jet subtracts enough of the LLTV’s mass to make it react as if it were in a 1/6 gee gravity field, allowing the pilot to maneuver his craft as if he were coming in for a lunar landing. Armstrong made over fifty LLTV landings before he landed on the moon.

If you want to know more about this craft, there is a half hour special full of information, old footage, and interviews with retired LLRV pilot and an engineer from the project. Huell Howser is the host. If you live in California, and you watch PBS, you know Huell. He is an acquired taste that I have never quite been able to acquire, but sometimes what he covers makes up for his idiosyncrasies. This is one of those cases. The program is California’s Gold #13003 – LUNAR LANDING. Try your local PBS station or check with the Huell Howser Archives at Chapman University.

184. Tail First

The first manmade object to leave the atmosphere and enter space wasn’t American or Russian. It was German. In 1942, V-2 rockets, first as prototypes, then as weapons, entered space routinely at the top of their high-arching flightpath.

That was the picture of spaceflight that lived in the heads of the kids of my generation. On Saturday morning TV shows, heroic young spacemen went off to save the universe and all their spacecraft looked like V-2 rockets. No wonder; this was pre-George Lucas and special effects were minimal. However, captured German footage provided plenty of shots of V-2s taking off.

These Saturday morning specials also landed upright on their tailfins. (Yeah, you guessed it. They ran the films backward.) On Dec 21, 2015, Elon Musk and SpaceX finally pulled that off in the real world. It makes me wonder what he was watching when he was a kid.

In the early days of serious thinking about space, when WW II was freshly over and the V-2 had shown the way, there seemed to be only two ways to land a spacecraft: either tail-first at a prohibitive cost in fuel, or by flying back in a winged craft. Neither was possible with the technology of the day, but the folks at Edwards Air Base were working on the latter, culminating in the X-15 (see 164. Flight Into Space). Later came the Space Shuttle.

In my novel Cyan, VTOL rocket shuttles are used extensively on Earth, and of course are the basis for landing craft on unexplored worlds. There won’t be any runways when we reach Alpha Centauri.

There is actually has a long history of craft designed to explore tail first landings.

X-13 Ryan Vertijet took off vertically, rolled over to horizontal while the pilot changed to a separate set of controls, carried out its mission in horizontal mode, then, at altitude, transitioned again to vertical mode. The pilot then slowly dropped toward the ground to land. The limitations that make this a technology demonstrator rather than a workable aircraft all become obvious near the ground.

Before takeoff, the Vertijet reached the airfield horizontally, hooked to and riding on a trailer. The trailer then lifted like a drawbridge until the Vertijet was vertical, dangling from a cable that hooked under the Vertijet’s nose. It took off from that position, and then returned to the trailer to land. As it approached the ground, traveling nose skyward, the pilot would slide his craft carefully sideways until the nose of his jet came in contact with a horizontal bamboo pole. Using that as a guide, the pilot then moved his craft toward the trailer until his nosehook came into contact with the cable. Then he cut his power; he had landed by reaching a condition of dangling from the cable, bellied up to the vertical bed of the trailer. The trailer was then lowered to horizontal, Vertijet attached.

Not very practical, but it did work. Only two Verijets were built and only a few operational flights were attempted.

The X-14 was of different configuration, with vanes to deflect its thrust. It took off vertically, but with the plane itself horizontal, in the manner of a modern Harrier.

The Lockheed XFV-1 had the power and the configuration for vertical takeoff and landings, but they never managed to work out the issue of pilot control. No successful vertical takeoffs or landings were made. It flew only conventionally with makeshift landing gear bolted to its belly.

The Convair XFY Pogo took off vertically, transitioned to horizontal, and made vertical landings, but only with great difficulty, and only with extremely experienced pilots. It was impractical, largely because the pilot had to look over his shoulder at the ground during vertical landings.

If we could salvage the rear vision camera from any 2016 sedan and send it back by time machine, any one of these craft would have been successful, but in the fifties the idea of looking at the ground while your eyes were skyward was pure science fiction.

Reaching on the moon would require a vertical descent and landing. They built a special craft to train astronauts for that mission. We’ll look at it tomorrow.

183. Roll Call for the Unremembered

Next week contains the anniversary of the first moon landing, and I intend to dedicate all posts to that event.

I grew up with Mercury, Gemini, and Apollo, but even I could not call out the names of all twelve men who landed on the moon without a crib sheet. The past seems to fade from memory as soon as it disappears from the rear view mirror. In the case of the early space program, that is a shame.

Here’s that crib sheet —-

Apollo 1 — Almost two dozen unmanned launches by various boosters tested hardware during the unmanned phase of Apollo. The scheduled first manned launch, AS-204, was renamed Apollo 1 after the capsule fire which killed Gus Grissom, Roger Chaffee, and Ed White on February 21, 1967. There had been growing anger in the astronaut corps over shoddy workmanship in the Apollo capsule, which boiled over after this unnecessary loss of life.

Apollo 7 — Don’t worry about the numbering oddity. It’s a mare’s next which is not worth untangling. Apollo 7 was the first manned Apollo flight. Apollo 1 was not a launch, since the disaster took place on top of an unfuelled rocket. Wally Schirra, Walt Cunningham, and Donn Eisele left the pad on October 11, 1968 to spend eleven days in orbit. Schirra had been particularly relentless in pushing for quality and safety during the year and a half delay. He retired from NASA after the flight, the only man to fly for all three programs.

Apollo 8 — The lunar lander was not ready and the Russians looked like they were about to attempt a moon landing., so NASA decided to gamble. Frank Borman, Bill Anders, and Jim Lovell launched December 21, 1968 for the moon without a lander. They entered lunar orbit, circled the moon ten times, then returned to Earth. They were the first humans to see the back side of the moon directly, although pictures had been sent back as early as 1959 – by the Russians.

Apollo 9 — James McDivitt (Commander), Rusty Schweickart (Lunar Module Pilot), and David Scott (Command Module Pilot) launched into Earth orbit on March 3, 1969 for a ten day mission. This was the first flight of a Lunar Excursion Module, and the first time the designations of individual astronauts became fully meaningful. After entering orbit, the command module with service module attached, moved away from the final stage of the Saturn, reversed, docked with the lunar excursion module which had been carried beneath it, and extracted the LEM. This head to head orientation allowed McDivitt and Schweickart to enter the LEM, detach it and test it in free flight while CM pilot Scott stayed in the command module.

Apollo 10 — The dress rehearsal. Launched May 18, 1969, Apollo 10 achieved lunar orbit, where Tom Stafford and Gene Cernan entered the lander, leaving John Young in the command module. They fired retros and descended to within 16 kilometers of the surface of the moon, did not land, reentered lunar orbit, and rendezvoused with the command module.

I have always felt that this has to be the most frustrating event in the history of space travel. Except, maybe, for Apollo 13. Or, maybe, for the six command module pilots who watched their crewmates successfully land on the moon.

Apollo 11 gets its own post next Wednesday, and the rest of the crib sheet comes after that.