Tuesday, May 19, 2015

Dragon landing

Dragon 2 has 8 SuperDracos in pairs each producing 15,000 lbs of thrust and throttleable to 20% (10% effectively since they are paired.)

Lowest throttle would be 12,000 lbs (4 x 3,000) total. Which is about what the Dragon weighs (landing would be more difficult if it weighed less than minimum thrust. If you didn't contact ground at zero velocity and shut down you'd go up again.) Landing legs should compensate for some imperfection.

From the pad abort test we learn that Dragon has 5 seconds of fuel at full throttle which would last longer at lower throttle settings. We assume it was fully fueled.

It went from zero to 100 mph in 1.2 seconds and reached 345 mph.

What is its terminal velocity in one atmosphere? I don't know. Somehow it would have to slow down enough to land on land, probably in less than a minute. I'd like to see that.

On mars it would make a crater, but SpaceX may bypass the wider red lander (Dragon version 3?) for the MCT. I guess we shall see, when we shall see?

Wednesday, May 6, 2015

The 'Just do it' architecture

This dismal report starts with this paragraph...
Significant strides towards the goal of sending humans to Mars have been made over the last few years, not only through advancements in planning and capabilities, but also in the political realm. However, despite this progress, there is a common misperception that there has been little or no motion forward in humanity's efforts and ability to actually achieve this goal.
Probably because 'can do' people understand that planning, while useful, is what you do before any moving forward actually occurs. Current plans seem more like, 'running in place and getting nowhere' plans. We can do better by identifying a simple truth: all plans fall short. Plus, we can turn the naysayers to our advantage by making them part of the plan.

The 'just do it' plan is based on the simple observation that all plans should have two major phases. 1) Getting enough supplies to a base location. 2) Only send colonists after enough supplies are waiting.

But how much is enough? What should the mix include? This is where naysayer input is valuable. We aren't going to be able to predict perfectly all the things the colonists are going to need. Humbly acknowledging this means sending less than what is required for survival wastes the entire mission. Sending more is only marginally bad and can't be avoided anyway, so why not embrace it?

We already know how to send stuff to mars, but should lower the cost. What lowers cost? Competition. So let's have one using just a small part of NASA's mars budget. The best part is we can implement this plan today instead of 20 years from now and avoid costly, decade long detours as well.

Every 26 month launch window, NASA will pay for one Falcon Heavy launch to mars. On board will be two 5.5 ton landers, each with a ton of cargo. The lander that safely lands first within a target ellipse gets $50m, the second gets $30m. We do this every launch window until sending colonists becomes irresistible to some private company. Let the naysayers come up with the cargoes.

Let the Russians or Chinese get there first and steal our cargo. It doesn't matter because the point is learning how to survive on mars. We just keep sending cargo. If we have to embarrass ourselves to get our act together, that works. It's also magnitudes cheaper than the progress suggested above.

This also allows NASA to save face regarding SLS/Orion. They can continue telling us Orion will put crew on mars, spending billions, while $200m a year goes unnoticed actually doing the mars mission. We've put rovers on mars costing billions while gaining valuable knowledge. It's time to take a fraction of that cost and actually move forward.

Tuesday, May 5, 2015

Second Mars Affordability and Sustainability Workshop

I intend to comment on this report.

...guide space agency leadership and national policymakers.
So they don't really consider commercial interests. To avoid flags and footprints economic viability is essential.

...[does] not endorse one-way missions to Mars, where the humans on the first mission are settlers.
Otherwise known as F&F. It doesn't have to be either/or. A MAV and ERV can be considered a separate mission.
...forward and backward contamination...
Please... contamination is a given. Get over it.
science exploration of Mars should be a major element
A huge mistake. The purpose of the first to land is to insure the survival of those that follow which then may include scientists. Scientists will get a lot more done if survival is not their focus. Others should ensure this first.
Can be done any where near mars, including from its surface. This is not a required precursor for anything. However, it would be stupid not to include these tools in the mix.
the technical capabilities required for human lunar surface operations are of limited applicability to human Mars exploration.

I. Background, Goals, and Structure
stepping stones
Identify those that really aren't and eliminate them to achieve lowest cost.
science goals enabled by human presence in the vicinity of Mars.
Fine as long as they don't interfere with the primary objective: Learning to survive and thrive on mars. We can move a lot faster than 20 years from now. We could be landing essential precursor colonist supplies today.

SLS/Orion are white elephants that will have nothing to do with mars.

II. Humans-to-Mars Architectures (they consider three.)
  (1) an “Apollo-style” mission (ruled out.)
  (2) an outpost w/ rotating, non-permanent crew.
  (3) colonization or settlement of Mars.
Colonization was not considered viable because they were doing it wrong. They had outpost thinking from the start and could not imagine anything else. The irony is an outpost is hugely more expensive and easier to abandon than just focusing on colonization.
Solar electric propulsion
Not essential, but could enable larger cargo mass to mars orbit. As long as we use existing technology rather than cause delay for something better, why not?
SLS-class heavy lift vehicle is required
Otherwise known as cognitive impairment and puts all other conclusions in question. Of course HL increases options. But SEP reduces the need for HL. The cost of one SLS launch cost about what 20 or more FH launches will. SLS will not fly at the frequency required either (if at all.)
sample return
Is not required. We already know general composition and the sample will not be from the actual crew landing site and wouldn't be representative even if it were.
2 to 3 SLS flights per year
Pure fantasy. Demonstrates not being serious about colonization.
Asteroid Retrieval Mission (ARM), fully utilizing the ISS, the highest-prioritynear-term “stepping stone” should be a long-duration, crew-tended habitat near the Moon
What are they smoking? Distractions that give more evidence they are not serious. These distractions cost ten years according to the report.

III. Humans in the Vicinity of Mars
All based on outpost thinking. This section can be ignored.

IV. Affordability and Sustainability
All about how to turn this into a jobs program to get political support.

Artemis project

Just for my reference.

Saturday, May 2, 2015

How obtuse am I?

Rand could not have seriously meant that I was ignoring asteroids.

So here I will make the comparison (between a planet like mars vs. asteroids as a mining source) that a comment in a post simply would not do justice to.

Consider your location to be fixed. Where ever you are, there you is. Even so in space (and I'm not being obtuse about orbits, so please.) A mine on mars is a fixed location away from you and can be mined for years. Other minerals, in other mines are also fixed positions relative to you. Even more important economically is you are the master of your own fate. You can individually exploit these resources.

Not so in space. Everything is in motion relative to each other. You live in a can of people, where chances are, you're not the captain. But let's make you the captain because that's an unavoidable fantasy for some. How do you exploit the asteroids? Your choices are... 1) move your can to the asteroid, 2a) move the asteroid to your can, 2b) move some of it to you.

Either option has a delta V cost. No asteroid is going to have the diversity of minerals you need, even if you don't deplete the minerals it does have. So you're back to making that choice again, captain. Your best hope is an ecosystem where other cans of people trade with you... meaning more delta V costs. Which is no where near as economical as hopping into your mars truck and picking up a load from the mine. Planet industry wins.

Well that was a lot shorter than I thought it would have to be?

Other factors? Getting colonist into space is basically the same cost other than landing. But with cans of people, more people means more cans. For planets you can reuse the ships, even landers when they're SSTO, used to transport colonists to a planet. So initially, because reuse takes some development, asteroids win; but soon thereafter planets win again.

The Emdrive may be the game changer.

Friday, May 1, 2015

Sounds foolish, but couldn't be more serious

When I say hereI could do an entire mars settlement program (evergreen) with just one year of SLS/Orion funding using just the FH for launch (13.2 ton is not only enough but preferred to larger vehicles.)

Assuming each year the interest pays for a FH launch with payload. That's two landers every 26 months leaving a habitat in mars orbit for a growing space station.  Assuming just one ton of payload per lander to the surface of mars or two crew with a month of supplies and personal property.

Supplies will continuously be sent until there is absolutely no doubt the colonists have a good start. Only then will colonists follow.

We will wait until we can send a minimum of six colonist on the first mission, then those colonist will decide what we send in the following landers.

It is expected that once living on mars is demonstrated, others will fund colonists in addition to those we send every launch window.