Musk to Mars

[fredinno]

On 2016-06-19 at 7:32 AM, CptRichardson said:

The last launch was two typical comsat birds, not Orbcom. So, yeah. If that $250-$500 mil figure is only for the LV, then SpaceX just blew that out of the water so hard that price escaped the solar system.

http://www.spacex.com/about/capabilities

No, SpaceX sells F9 for $62 million. Thus, the satellite, if it is $250 million, the satellite costs 4X the launch cost.

On 2016-06-18 at 9:12 PM, PB666 said:

Lame. 

https://en.m.wikipedia.org/wiki/Boeing_702

1700 to 3000 kg. From the wiki, and i expect this to satisfy your squirm. 

On June 1, 2015, it was announced that ABS was so happy with the performance of ABS-3A, even before it reached its operative orbit, that they decided to order a new 702SP, ABS-8, to be launched by late 2017. When launched on a Falcon 9, the total investment was so low that it would be profitable even if they do not find another satellite to pair it for the launch.^[19]The failure to renew the charter of the Ex-Im Bank during 2015 meant that it couldn't finance the operation. As such, the order was not finalized, but Boeing and ABS were still in talk for possible options.^[20]

https://en.m.wikipedia.org/wiki/SSL_1300

Those are the platforms for the latest launch. The second of which The platform for the Eutelsat 117 West B satellite is also the platform for the most powerful broadband satelliete currently in operation. 5500 to 6000 kg mass.

 

For the biggest satellites, you would use a FH rocket... which should also let you launch directly into GEO, meaning a longer satellite lifetime/margin fuel.

For smaller satellites (mainly 8-10T to LEO class), I would say use a F5 FT. If it existed. If SpaceX used modular F5s instead...

[PB666]

4 minutes ago, fredinno said:

http://www.spacex.com/about/capabilities

No, SpaceX sells F9 for $62 million. Thus, the satellite, if it is $250 million, the satellite costs 4X the launch cost.

For the biggest satellites, you would use a FH rocket... which should also let you launch directly into GEO, meaning a longer satellite lifetime/margin fuel.

For smaller satellites (mainly 8-10T to LEO class), I would say use a F5 FT. If it existed. If SpaceX used modular F5s instead...

Just pair or more sats, no problem. 

[fredinno]

12 minutes ago, PB666 said:

Just pair or more sats, no problem. 

No, it IS a problem. That multi-satellite Oorbocomm launch was only 1.2T in payload.

And LEO/MEO sats can rarely be dual launched, since they generally go into different orbits. Unless they are in a consteallation of smallsats, but that generally isn't the case.

[PB666]

14 minutes ago, fredinno said:

No, it IS a problem. That multi-satellite Oorbocomm launch was only 1.2T in payload.

And LEO/MEO sats can rarely be dual launched, since they generally go into different orbits. Unless they are in a consteallation of smallsats, but that generally isn't the case.

If you have enough fuel for meo you can drop sats in leo and then burn to meo do a partial circ with the fuel left and deploy sats. Problem solved. 

[Gaarst]

30 minutes ago, PB666 said:

If you have enough fuel for meo you can drop sats in leo and then burn to meo do a partial circ with the fuel left and deploy sats. Problem solved. 

Trajectories taken for a LEO or GTO/SSO/MTO/whatever are different.
This is why Ariane 5 only launches dual satellites to GTO (or whatever other launcher launching multiple sats), and why there are two different variants for LEO (ES) and GTO (ECA).

[PB666]

 

[fredinno]

On 2016-06-18 at 9:12 PM, PB666 said:

Lame. 

https://en.m.wikipedia.org/wiki/Boeing_702

1700 to 3000 kg. From the wiki, and i expect this to satisfy your squirm. 

On June 1, 2015, it was announced that ABS was so happy with the performance of ABS-3A, even before it reached its operative orbit, that they decided to order a new 702SP, ABS-8, to be launched by late 2017. When launched on a Falcon 9, the total investment was so low that it would be profitable even if they do not find another satellite to pair it for the launch.^[19]The failure to renew the charter of the Ex-Im Bank during 2015 meant that it couldn't finance the operation. As such, the order was not finalized, but Boeing and ABS were still in talk for possible options.^[20]

https://en.m.wikipedia.org/wiki/SSL_1300

Those are the platforms for the latest launch. The second of which The platform for the Eutelsat 117 West B satellite is also the platform for the most powerful broadband satelliete currently in operation. 5500 to 6000 kg mass.

 

I wonder if F9H will ever be able to do Ariane-6 esque dual launch...?

On 2016-06-22 at 6:29 PM, Gaarst said:

Trajectories taken for a LEO or GTO/SSO/MTO/whatever are different.
This is why Ariane 5 only launches dual satellites to GTO (or whatever other launcher launching multiple sats), and why there are two different variants for LEO (ES) and GTO (ECA).

This. Inclinations are a pain in the ass. GEO sats all tend to go to one. Not the case for LEO, or MEO.

[tater]

Mars itself seems like a non-starter to me in the foreseeable future past a short visit, and even that is pretty non-trivial. The radiation environment in transit, and on Mars is a real problem. They better spin the transit vehicle, or substantial, permanent health issues will result (ISS style exercise regimes only slow the deterioration, they don't stop it). With all that, we don't even know if 1/3 g is enough. On top of that, any hab on Mars needs to be under 3m of soil.

[peadar1987]

On 18/07/2016 at 6:00 PM, tater said:

Mars itself seems like a non-starter to me in the foreseeable future past a short visit, and even that is pretty non-trivial. The radiation environment in transit, and on Mars is a real problem. They better spin the transit vehicle, or substantial, permanent health issues will result (ISS style exercise regimes only slow the deterioration, they don't stop it). With all that, we don't even know if 1/3 g is enough. On top of that, any hab on Mars needs to be under 3m of soil.

Not really. People have regularly stayed on the ISS longer than a transit to Mars would take without permanent damage.

The radiation risks, while not insignificant, are also not a deal breaker. On the surface, you'd be taking a dose of about 240mSv a year, unshielded. Each 1 Sievert you absorb raises your risk of eventually developing cancer by 5.5% (less if you are older). A 40 year stay (unshielded) would increase your risk of cancer by about 55%. You can reduce this further with small, inexpensive amounts of shielding, for example, by having bunks surrounded by water tanks, or even sandbags, which, depending on how long the astronauts sleep, could knock almost a third off the radiation dose.

To put that in perspective, being a lifelong smoker is estimated to approximately double your risk of cancer (the estimates on this do vary though). A serious concern, but not mission-ending. 

Edited July 20, 2016 by peadar1987

[tater]

I'd be most worried about acute issues, like bone loss. Presumably 0.38g helps, but I think a precursor study would be to have a spun hab in Earth orbit at martian gravity to see. If that eliminates the bone loss problem, it would be a big deal, because then the transit times would have an intervening reset---that might be another study, send people to ISS, measure bone loss, then send them to the 0.38g station and see if it results in regeneration.

[Nibb31]

Bone loss can be fought with medication, including some of the same molecules that are used on earth against osteoporosis.

Muscular atrophy and cardiovascular problems can be fought be exercise.

The most troublesome issue at this point are the optical nerve and ocular issues. There might be pharmacological remedies against those symptoms too, but they have yet to be experimented on the ISS.

If we have to wait until we have developed and tested orbital centrifuges, then nobody is going to Mars for the next 30 years.

[tater]

I'm not sanguine about humans going to Mars in the next 30 years anyway  .

It is my understanding that current bone loss mitigation efforts are just that, they mitigate bone loss, but do not prevent it. Note that the losses experienced on long ISS missions to this point are in spite of their exercise regimes.

[Emperor of the Titan Squid]

4 hours ago, tater said:

I'm not sanguine about humans going to Mars in the next 30 years anyway  .

It is my understanding that current bone loss mitigation efforts are just that, they mitigate bone loss, but do not prevent it. Note that the losses experienced on long ISS missions to this point are in spite of their exercise regimes.

I f you dan't think this will happen , read the Case for Mars.

Edited July 20, 2016 by Emperor of the Titan Squid
Correcting a spelling error.

[tater]

1 hour ago, Emperor of the Titan Squid said:

I f you dan't think this will happen , read the Case for Mars.

Mars has been "around the corner" since I was born. Forgive me if I think that current claims are no more likely than all the other efforts (and the vast quantities of money sunk into them).