Kelly describes medical issues from weightlessness
In prepared remarks to a congressional subcommittee today, astronaut Scott Kelly described the medical problems he has experienced since returning from his 340 day mission on ISS.
Kelly claimed in these remarks that weightlessness caused permanent effects (which this news article decides to emphasize), but I think that might be an overstatement. None of the specific problems he experienced appear to be permanent ones, and in my interviews with Russian astronauts who stayed even longer on Mir they noted no permanent effects. One did say however that the recovery time tended to match the mission time, so that if you spent a year in space it took a year to completely recover. Kelly has only been back about three months, so his recovery is certainly not over yet.
Update: Kelly’s remarks were part of a hearing promoting legislation that would give astronauts lifetime medical coverage from the government. Thus, there is a bit of lobbying going on here.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
In prepared remarks to a congressional subcommittee today, astronaut Scott Kelly described the medical problems he has experienced since returning from his 340 day mission on ISS.
Kelly claimed in these remarks that weightlessness caused permanent effects (which this news article decides to emphasize), but I think that might be an overstatement. None of the specific problems he experienced appear to be permanent ones, and in my interviews with Russian astronauts who stayed even longer on Mir they noted no permanent effects. One did say however that the recovery time tended to match the mission time, so that if you spent a year in space it took a year to completely recover. Kelly has only been back about three months, so his recovery is certainly not over yet.
Update: Kelly’s remarks were part of a hearing promoting legislation that would give astronauts lifetime medical coverage from the government. Thus, there is a bit of lobbying going on here.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
He wants government funded health care! For free, many people would do what he did just for the experience and not worry about who is going to pay for health care.
The Space Show had a NASA rep on a while back and when asked about mitigating the effects of spending long periods in space her answer was, just go faster. She said their prefered course of action wasn’t solving the health problems but rather just going places faster so that they wouldn’t be an issue.
Of course, we aren’t doing that either. This random guy on the internet’s opinion is that we need to do both.
Getting places faster will certainly help but will also increase the number of destinations we can get to. Also, it is desireable to have space stations within the cognitive horizon of destinations and here we will need things like variable gravity. We need to know if it is effective.
> Getting places faster will certainly help but will also increase the number of destinations we can get to.
A round trip Mars mission would take about 2.5 years to complete using chemical rockets. Once we gain that experience with equipment reliability, radiation shielding, and artificial gravity, we might consider destinations further out. Using solar electric propulsion, we could pre-position supplies and do automated set-up and shielding of inflatable habitats.
The one-way Hohmann transfer time for the following is:
– 1.1 years – Vesta
– 1.3 years – Ceres
– 2.7 years – Jupiter
– 6.0 years – Saturn
With 50 g/cm2 of shielding during the crew’s sedentary time, a nominal 47 year old male (1,000 mSv) could spend 4.5 years in free space before reaching his career limit. Tether and spin up could provide a full 1 gee.
So in stepwise manner, gaining experience and confidence, we might be able to establish permanent bases and continue to supply out as far as the moons of Jupiter before needing to have advanced propulsion.
Hohmann transfer orbits are the most fuel efficient for chemical rockets but they are unacceptable for manned missions beyond lunar orbit. The transit time may be acceptable for a robotic cargo missions, but spending years in a totally self contained environment without resupply and without any possibility of rescue or even assistance following the inevitable failures is a recipe for making disaster a commonplace occurrence.
The only war humanity will be able to travel routinely between planets will be to increase speeds exponentially.
Chemical propulsion requires far too much fuel.
Continuous ion propulsion even a low thrust can achieve high velocities over long periods of time. The constant acceleration would also have added benefit of providing an artificial gravity, decreasing the physiological effects of prolonged microgravity.
If a method can be developed to capture the (tenuous) solar wind, that may be used as a supplementary propellant.
Of course missions beyond the asteroid belt will be necessity require nuclear power.
DougSpace,
Thanks for the analysis.
I have seen ideas to use the rocket that inserted the crew’s spacecraft into the Hohmann transfer orbit as the counterweight on the tether, for creating artificial gravity. It seems like a good idea, but I think we need more experience with tethers before committing to it.
A few weeks ago, I read “Saturn Run,” science fiction in which the story discussed how advanced propulsion could reduce the one-way time to planets, as far away as Saturn, to months rather than years.
The NERVA (Nuclear Engine for Rocket Vehicle Application) engine puts almost all its energy into heating the propellant:
https://en.wikipedia.org/wiki/NERVA
The VASIMR (Variable Specific Impulse Magnetoplasma Rocket) has some advantages, but there would be an enormous amount of waste heat that would have to be radiated away:
https://en.wikipedia.org/wiki/Variable_Specific_Impulse_Magnetoplasma_Rocket
Neither engine has flown.
I expect that we will explore our solar system in a relatively slow pace (stepwise is a good word for it), and many of the permanent installations will be built and operated by commercial companies who have found ways to make money in space, such as mining the moon or asteroids in order to build space hardware or high-value goods for Earth consumption.
The lunar poles may be a good location for an early mining facility, as the water that is almost certainly there could be used as fuel that would not have to be brought out of the Earth’s gravity well. From the poles, an expedition could set up radio telescopes on the far side of the Moon so that they would be shielded from all the radio noise coming from Earth. This may give radio astronomers a couple of decades of noise-free investigation of all or most wavelengths, not just the very narrow bands that were set aside for them.
Going faster would either require alot more fuel, extra launches, or a new technology like nuclear thermal propulsion or maybe nuclear electric ion. Hohmann transfer to Mars takes six to nine months depending on during which conjunction it is done. 2024 is a far away conjunction while 2033 is a close one. Total mission time will be about 26 month in eiter case, just a few more months spent at Mars instead of on the road during close conjunctions. 6-9 month is what astronauts spend at the ISS now. If 0.38g is fine, then there is no need to use simulated gravity until we go further than Mars. That is the explanation for why NASA never has launched any centrifuge. The problem does not exist, although it would be nice to test 0.38g in LEO to make sure. Should be no problem for bones and muscles, but there could still be a higher liquid pressure in the upper body and thus maybe an eye problem (only for men, funny enough).