Panel Recommends Space Science, Not Stunts

wisebabo writes "A panel reporting to President Obama is recommending that we skip landing on the Moon and Mars and instead consider progressively deeper space voyages (first to the L1 Earth-Moon point, then perhaps the L2 Earth-Sun point, then a Mars flyby/orbit or asteroid visits). While in Mars orbit, the astronauts could send robotic probes to land on the surface, which could be much more effective than current rovers without the 10-minute time lag to Earth. I, for one, whole-heartedly agree that this approach would lead to 'the most steady cadence of steady improvement,' and keep us from inconsistent achievements in space (like not leaving Earth orbit for 40 years). Some would say that this approach would be lacking in the photo-ops necessary to maintain interest in the space program (no footprints on Martian soil) but I think there would be plenty of cool vistas — perhaps a rendezvous with a comet, or even orbiting one of the moons of Jupiter, assuming they figure out radiation shielding — to keep the taxpayer dollars flowing. The science return would be much greater because it would hopefully utilize both man and machine at their best; robots on one-way trips down into a gravity well while the humans provide the intuition and flexibility from orbit."

Wrong

[feder]

A panel reporting to President Obama is recommending

The Augustine commision presents options - not recommendations.

Martian Time Slip

[mbone]

than current rovers without the 10-minute time lag to Earth.

At opposition, the average round trip time (RTT) to Mars is 9 minutes.

At superior conjunction, the average RTT to Mars is 42 minutes.

At other times, the RTT will be in between these two values.

Both of these numbers will vary at the 10% level due to orbital eccentricities and inclinations, but, clearly, most of the time the RTT will be greater than 10 minutes.

However, this is almost irrelevant. All currently and planned rovers or landers use "bent-pipe tracking," where data is sent to an orbiter, and then the orbiter, sometime later, sends it to the Earth. This greatly increases the effective RTT (there are not orbiters passing over any given surface location at any time).

I believe that the Phoenix, the current rovers, and the Mars Science Laboratory all basically plan on an effectively daily RTT (i.e., at best one up and down link per day). These long effective RTTs and the use of orbiters to store-and-forward data are part of the motivation behind the efforts around Delay / Disruption Tolerant Networking (DTN [dtnrg.org]) - AKA the Interplanetary Internet.

Re:Ground to Orbit is the key

[Shadowmist]

At the moment, that takes physics which simply does not exist yet. Hard reality of ground to orbit is that you've got throw 90 percent of your spaceship's mass away to get there.

Teleoperation from orbit makes sense

[Geoffrey.landis]

I can see an argument of humans vs space probes, but the idea of putting the humans in orbit to release the space probes seems to be the worst of both worlds.

If we are going to send humans out there, they should be landing on something, otherwise send probes.

It turns out that the last 200 kilometers, getting from orbit to the surface and back, is vastly, completely, incredibly the hardest part. It is much, much simpler to get humans into orbit than to land them on the surface of Mars. Among other things, to land on the surface, you need design, build, test, quality, and fly two additional vehicles, a lander vehicle and a launch vehicle, both of which are flying in regimes that are hard to engineer for. Not to mention a long-duration habitat for the Mars surface, and spacesuits that will survive for hundreds of EVAs on the Mars surface-- not easy.

Orbiting Mars is vastly simpler than landing on it.

Of course, I've talked and written on that subject many times before-- Teleoperation from Mars Orbit: A proposal for human exploration [elsevier.com], Footsteps to Mars [geoffreylandis.com], etc.

(I agree, however, that L-1 is silly-- nothing there to explore.)

Re:Public Attention

[cunniff]

Why WERE we going back? Did we really "get what we paid for" on those later trips to the moon? It sounds like engineering for engineering's sake more than science for science's sake.

Actually, it was the later missions that provided most of the science return of the Apollo program. Apollo 11's crew only spent a couple of hours EVA on the surface, collecting some photos and a few only moderately-well-documented samples. Apollo 12 increased that to 7 hours, and returned samples from Surveyor 3, providing us with data on the lunar environment. Apollos 14, 15, 16, and 17 landed at many diverse sites, including the lunar highlands, Hadley Rille (a volcanic lava tube remnant), and the lunar mountains. They deployed a much larger science instrument package than Apollo 11. They returned well-documented rock and core samples and provided information that later supported the new "massive collision" theory of lunar origin.

So, if you're talking scientific return, Apollo 11 was the least valuable of the landings. Any serious scientific exploration must include multiple missions.

Re:Teleoperation from orbit makes sense

[lalena]

Plus, landing robots is getting easier. Look at the recent success with designs that use parachutes + inflatable balloons and have the lander bounce around until it stops. Can't do that with people. The KISS principle works here.