In this guest editorial, my 40 year pal Joe Carroll... who is "Mr. Tether" for saving that now-useful space technology, back in the '80s... puts forward twenty-five provocative 'theses' or assertions about spaceflight across the next generation or so.
Joe takes into account what's been announced so far, especially about Elon Musk's SpaceX 'Starship program,' offering some points that may need to be solved... or at least resolved based on sound arguments.
You are all welcome to initiate discussion in comments, below!
Theses on Starship, Tourism, and Human Futures Beyond Earth
It is useful to periodically reconsider our prospects and options for living beyond Earth. The theses listed below are intended to stimulate more serious discussion of some currently popular scenarios. These are assertions. Some may be disproved, but most are way-under-considered.
Use the comments below to get the discussion rolling, then restart by consensus elsewhere.
Regarding SpaceX Starship
S1. Starship’s main business will be delivering payload from Earth to LEO (& back), not beyond.
S2. Starship may cut LEO $/kg by 100 binary (i.e., only 4-fold), but still revolutionize use of space.
S3. Once launch prices drop ~4-fold, most customers will focus on launch vibration & reliability.
S4. The STS orbiter cost more per kg than its main engines. That may also be true for Starship.
S5. Simple “Startankers” can cost & weigh ~1/3 less & deliver >1/4 more payload than full Starships.
S6. Most useful early LEO propellant transfers will be from one Startanker to a Falcon stage 2.
S7. Later transfers will be to lighter (inflatable?) stages, with lower T/W than Falcon or Starship.
S8. It is better to find local use for most hardware far from LEO than to return it for later reflight.
S9. Any military point-to-point payloads will land on their own, with Starship landing elsewhere.
Tourism and Commercial Space Travel
T1. Early “point-to-point” travel needs a transfer hub in LEO, to grow markets for direct routes.
T2. A LEO hub is also a great meeting site, and a hub for orbital tourism & settlement testing.
T3. For science/health - + for space novices - a LEO hub can rotate-emulate Moon & Mars gravity.
T4. A “2001 wheel” won't minimize spin-queasiness. Best is a long, slow-spinning dumbbell.
T5. Outboard capture & de-orbit by tether allow transfers in gravity, and can boost payload ~10%.
T6. Most tourists will want access to 0g, but prefer partial gravity for most of their time in orbit.
T7. Easy elevator access to a range of gravity levels may be a key attraction for tourists & retirees.
Human Futures Beyond Earth
H1. It is harder to live in the best place off Earth than the worst place on Earth (except volcanoes).
H2. The best way to start “mining the sky” is to recycle & reuse most mass now discarded by ISS.
H3. Growing food in LEO can get us closer to living off Earth than putting people on Mars can.
H4. The US needed Apollo, in a hurry. We don’t need footprints on the Moon or Mars in a hurry.
H5. After decades of refining 0g health countermeasures, human health still goes downhill in 0g.
H6. Around our sun, Earth is the only livable ~1g body. All others have 3/8g, ~1/6g, or <0.09g.
H7. We know nothing about sustained human health between 0g & 1g (Apollo stayed 1-3 days).
H8. We can find the effects of 1/6g & 3/8g far safer & cheaper in LEO than on the Moon or Mars.
H9. The only place we can settle off Earth without meters of shielding is LEO inclinations <15o.
Joe Carroll January 8, 2022