Time-in-Space Record Broken

NoFrance writes "Russian cosmonaut, Sergei Krikalev has taken the record for most time spent in space away from fellow Russian Sergei Avdeyev. At 748 days in space, Krikalev has an impressive list of accomplishments to his name, including : back-to-back 6 month tours on mir, he flew on the first joint US-Russian space shuttle mission, and a member of the first crew to live on ISS. He is currently commander of the ISS in a six-month stint that began on 14 April. Most impressive is his ability to deal with the physical hardships in space. In space most people lose around 1.5% of their bone mass per month, even with a disciplined exercise regime. And growing the bone mass lost from a 6 month stint back, can take a long time."

Comments

Calcium suppliments don't help

[everphilski]

Calcium suppliments don't help. The problem is your body realises that you have too much muscle mass and that you are too strong for microgravity, so it stops reinforcing your bones until it percieves a need to strengthen your bones. It's not a lack of available calcium. It is the exact same phenomenon that plagues people on bedrest. Even though they are given the best food and nutrition available when they are off bedrest they are weak and frail.

-everphilski-

Great Wikipedia link ... Michael Foale, 373 days

[Shivetya]

http://en.wikipedia.org/wiki/Spaceflight_records#T otal_time_in_space_-_top_50_space_travelers

Re:Artificial Gravity

[Cyclotron_Boy]

Centripetal-force-generated artificial gravity systems, like those envitioned by Arthur C. Clarke shown in the film 2001, have been studied by NASA and the Air Force for decades. Basically, it would require a structure of a few hundred meters radius rotating at a few rpm. The scale of such a habitat would be enormous, and the cost associated has not been shown to be warranted as of yet. However, the commercialization of space will probably bring about such an innovation out of necessity (for comfort).
Links here, here, and here.

Re:artificial gravity

[Red Flayer]

There is no simple artificial gravity solution.

I'm sure every slashdotter has seen multiple sci-fi examples of a huge spinning doohickey that replaces gravity with centrifugal[1] force.

Four problems I can see:

1) If the radial arm is too short, there are tons of biological side effects. Coriolis forces and angular momentum are the two major factors causing these side effects, which can be mediated by intermittent spinning.

2) An engineering nightmare, especially if done intermittenly.

3) A logistical nightmare. If the radial arm is long enough to prevent the side effects, construction and maintenace service would, I believe, be beyond acceptable costs.

4) Would make impossible all the long-term zero-g experiments we need to continue doing.

However, there is currently renewed research into the idea. I was able to find an entry for the Mars Gravity Biosatellite in Wikipedia, but there is not much information there.

Anyone know more info (such as projected launch date) about the MGBS or other artificial gravity experiments?

[1] Yeah, yeah, it doesn't really exist. But it's a useful term.

Re:748 days?

[johno.ie]

Micheal Foale a British born astronaut with dual US/UK citizenship has spent 374 days, 11 hours, 19 minutes in space. I believe this is the extra-Russian record.

Re:question

[visgoth]

Calcium supplements wouldn't help, but there is work being done that may one day lead to a suppliment that would prevent bone loss.

Re:How do you regain bone mass?

[Dunbal]

what else makes the bone mass come back?

I can answer that. Although this comes as a surprise to many people, bone is actually living tissue. It undergoes two continuous processes. On the one hand bone is continually reabsorbed by the body, and the minerals (mostly calcium and phosphate) end up in the blood stream. And on the other hand, new bone is always created as well. Those self same minerals are taken out of the bloodstream and deposited to make new bone.

      Now the problem occurs because of the following. One of the main factors that determines where and how new bone is deposited is the constant traction against the bone by tendons. These tendons are attached on one end to the bones, and on the other to muscles. So muscle activity, which puts tension on the tendons, actually favors bone formation along the stress lines in the bone.

      The only problem is that there is just so much muscle activity that you can get from an excercise program. This pales in comparison to the CONSTANT activity that your support, or anti-gravity muscles are doing all the time, 24hrs a day, in an involountary fashion. Now in space, the effects of gravity are gone. So the anti-gravity muscles stop working. So you end up losing the most part of the stimulus that promotes new bone formation. Hence, you get bone loss. The rate of reabsorbtion is now greater than the rate of formation.

      How does it come back? Only through time, excercise, GRAVITY, calcium supplements, vitamin D, and in extreme cases, PTH (parathyroid hormone). Although the physiological function of this hormone is to promote bone reabsorbtion (ie loss), no one is sure why it actually does the opposite when used as a drug. Remineralizing a bone is a slow process however. This astronaut will NEVER get back to where he was when he left Earth.

Re:10m+

[AKAImBatman]

The Mars Direct plan calls for a maximum of 130 contiguous days in space (on the return trip) with three other people, using chemical rockets

Yes, I see:

Use of a nuclear thermal rocket (NTR) third stage on the Ares would increase trans-Mars payload by 50%. The NTR stage would have a specific impulse of 900 s, a power of 900 MWth, and a thrust of 45,000 lb. Use of a NIMF (Nuclear rocket using Indigenous Martian Fuel) stage on the lander would provide the Habitation Module with the capability of leaping from one location on the Martian surface to another, using compressed Martian carbon dioxide from the atmosphere as propellant. This would allow 18 sites on the surface to be visited within the 550 days of surface time, as opposed to just one for the baseline expedition.

;-)

Re:10m+

[Rei]

Orion (actually, Medusa - Orion is dated and inefficient) is hardly the only high ISP/high thrust nuclear propulsion method available. In addition to nuclear thermal (not as high ISP, but no EMP and little to no radioactive waste, so can theoretically be used in Earth orbit), there are the antimatter catalyzed microfission and microfusion engines, and fun things like nuclear saltwater engines (dirty, but no EMP - you have subcritical fissile salts in water kept in neutron-absorbing capillaries; the water is injected into the engine, where it goes critical)

There are lots of neat currently-achievable nuclear low-thrust methods as well.

Re:748 days?

[daniil]

See, it's very simple. The man who spent 438 days in space on a single mission is Russian, while the man who has spent 375 days in the space altogether is an American. The American single mission record is 193 days.

Re:10m+

[AKAImBatman]

We need to figure out how to get rid of the fallout though

Supposedly, they have. Pratt and Whitney only need a buyer before they start constructing the engines. The engine is a tri-mode jobbie that can do high Isp thrust in space, and low (for NTR) Isp afterburning for high thrust, atmospheric work. Once in space, the engine can idle to produce ship's power.

Nice engine, eh? I want one. ;-)