Saturday, September 22, 2007

Throwing my weight around

Let’s say the impossible happens and *I* get to control 50 mil of NASA’s bloated budget. (less than 1/300 of the total!)

I’d do two things:

First) I’ve blogged before about the dirt-cheap Mars sample-return plan: Perform a major search for bits of Mars that are already here. The easiest place to look is Antarctica - that's how we found ALH84001(*3). There are only a few known Martian meteorites, a program like this could easily double that number. And one of the new finds could be the Holy Grail (definite proof of life) we're looking for.

Just to start the ball rolling - we could send out Antarctic explorers for 50K per explorer per year (we‘d be turning away volunteers by the tens of thousands!). So it would be possible to send a crew of 100 for 5 mil per year. I think we’d turn up something interesting!

Second) Start actual R&D with tethers. (Browse that website - *very* cool and there are even other Tether companies out there. But IMHO this is the best). A tether consists of a central mass and a long rope - say 10 or 20 miles. The tether and payload are in orbit around Earth, spinning around each other like a gigantic bolo. It has one massive side and one small side (the payload). By letting go of the payload at the right time, the tether is able to throw a payload on ballistic trajectories anywhere in the inner Solar System. The max payload is about a tenth of the central tether mass.

I'd love to put one around Earth, then launch a tether to the Moon, then they could start playing catch with a small "ball" (which could be as low-tech as a bucket of rocks and a radio transmitter). We'd learn a ton from a year's worth of experiments like this. After playing catch for a while, we could even practice soft-landing the ball on the Moon & picking it up again. If we lose it, no biggie, they’re practically disposable. In fact, the bulk of the tether mass could be spare ‘balls’!

The round-trip time for the ball would be about a week, and then the tethers would take time to restore their orbits. We would also need to practice tossing a payload from the end of the tether to the central tether mass.

All this seems doable for ~40 mil - so I’d spend 10 mil looking for rocks and 40 mil on tethers.

This idea is hardly original with me - it is basically wrapping a mission around and

It is a brilliant idea to explore... getting outside the stupid LOG function in the Rocket Equation [ ] is absolutely key to exploration of the inner Solar System for far less fuel/cost/mass than otherwise. Until viable fusion rockets are available (50-100 years), this seems like the optimal solution.

Once the tethers are in place, all the miles are free. Let’s say we get the central mass of the Earth tether up to 25,000 kg - this could be spent fuel tanks from the Shuttle, buckets of rocks - anything really!

Now we could deposit 2500 kg on the Lunar surface for the cost of getting it to LEO.

Now, the fun part to consider is - if we were really able to deposit 2500 kg on the Lunar surface for (almost) free - what sort of infrastructure could we build up over time? Obviously, this type of capacity could be used to resupply a (nonexistent) Lunar base with food/water - but could we do other things?

Here's a list:

1) Tell top American colleges that if they design a rover, we'll park it on the Moon. Solicit proposals, take the top 5, give the top5 schools 200K in development money, and a year later, launch the rovers. We'd have to hitch a ride to LEO & that's it. The only requirements: the rover must be mobile, capable of teleoperation, include a videocamera, and be < 2500 kg. (*2). Total mission cost: $1 mil to develop the rovers, 5 - 50 mil to launch them. We could even partner with a TV network to run a 12 week weekly show, 1 intro, 5 rover builds, 5 rover launch/landings, 1 wrapup. Put it on prime-time, and I'd bet people would watch - plus, it would establish an entertainment link to a real space mission.

2) Set a rover (maybe even one of the above 5) down at the poles, check out the water ice that is almost definitely there.

3) Land a small electric-powered bulldozer/rover near one of the water-ice (?) sites at the poles. Dig a trench. Land a second one, dig more... If the trench were (say) 8 feet deep, 8 feet across, and 30 feet long, it would be suitable for low-tech human occupation. A small dozer or two could dig this, given enough time. If the trench were near the poles, the Sun would never appear overhead - so most of the trench would be in the shade all the time and we wouldn't need to cover the roof to avoid solar radiation. The dozers could dig until 2/3 of the battery capacity were exhausted, then climb out, maybe climb a small hill, and position themselves for solar recharge - which could take as long as a couple of weeks, but we've got time. When the trench is completed, we could try sending up an inflatable hab that would fit in the trench and be light enough for the tethers to throw. Would this work? No idea! But if it did, it is even possible we could do a quick manned mission with the tethers. Send up some food & water, a couple of space suits, some kind of heater. Send up some scuba air tanks on a separate trip & use them to inflate the hab. Another nice advantage of tethers is that they can be tested repeatedly prior to actual use - obviously, we would take advantage of this prior to anything risky.

Since the Moon has no atmosphere, in theory the tether can set payloads gently right on the surface.

4) Land a rover near the Apollo 11 landing site, check it out.

5) Sample return - tethers optimize this beautifully. In fact, we should and could use this for the Mars sample-return mission. It would be very useful to install a Mars tether during the course of something we were going to do anyway.


(*1): The first referenced PDF file shows 85 days for the tether exactly as defined in the paper. Obviously, if we change key parameters (mass of the system, length of the tether), we change this figure also.

(*2): Getting our payload to LEO will cost some, but no more than $20,000,000. (the current price for launching a person to the ISS) Or - as long as we're into tethers - check out , we could do it with a high-altitude plane launch.

(*3) This is the Mars meteorite announced by NASA in '95 or so to contain proof of Martian life. The 'proof' is a bit lacking; the jury is still out. We know it's from Mars from the analysis of gases trapped in tiny bubbles in the rock. They're like nothing on Earth and they are very similar to what we know is on Mars

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