SpaceX and Starship
Starship SN5 static fire testing has been postponed again. It's beginning to look like SpaceX has a strategy of using rolling road closure dates. Rather than continuing to report on "plans" and the associated delays, from this issue forward, I will focus on actual tests and launches, at least as far as near-term missions go. More signal and less noise is a good thing.
Earlier today, 20 July, an H-IIA rocket launched from Tanegashima Space Center in Japan, carrying a Mars orbiter called Hope, developed by the United Arab Emirates. That was the 36th consecutive successful launch for the H-IIA. The orbiter will arrive at Mars in Feb 2021. Hope's mission objective is to provide a comprehensive image of weather dynamics on Mars.
Two more missions to Mars are planned during the current launch window: Tianwen-1 from China, and NASA's Mars 2020 mission, both of which are landers.
The specifications for both Super Heavy and Starship will undoubtedly continue to evolve as the development process continues. The current numbers, as published by SpaceX, are that SH will be 70m tall, and Starship will be another 50m on top of that. Together, that's an astounding 120m. Compare that to the Saturn V, which was 111m.
A few other numbers of interest:
Diameter: 9m
Payload to LEO: 0.1M kg
Starship propellant: 1.2M kg
Super Heavy propellant: 3.4M kg
Super Heavy thrust: 72 MN (16 Mlbf)
Starship liftoff (wet) mass: 1.4M kg (my estimate)
Total SS + SH liftoff (wet) mass: 4.94M kg (my estimate)
Although Elon has expressed a desire for an even 42 Raptor engines total, it looks like the current design will only have 41: six on Starship (3 sea level nozzles and 3 vacuum), and 35 on SH. It has been suggested that SH will end up being somewhat configurable in this respect, with a few less engines when payload mass allows.
The upcoming Starship SN5 test will only have one of those 6 Raptors. Due to the way the engines are arranged on the base, as you can see in the image below, just one engine won't have its thrust vector directly aligned with the vertical center of mass on the ship; some nozzle steering plus attitude control jets will be needed to keep the vehicle upright. That means takeoff and flight may look a little unusual, which could certainly add a little extra flavor to the upcoming hop test.
The first reports are coming in from people who have received their antenna from Starlink for beta testing. Very exciting!
Getting Ready
In the last issue, we were working our way through some ideas for things to take along with us to Mars. If you were permanently moving there, the number and types of things you would want to bring increases significantly. It wouldn't be like going somewhere on Earth and staying in a resort hotel, where supplies are available to meet your needs. It would be more like traveling to the middle of an almost empty desert. You will have a roof over your head, a source of water and basic food, and that's about it.
You would need to bring all of the other things that fill a typical home, such as a bed, bathroom supplies, cooking gear, silverware, glassware, and so on. You should also think about past-times. How will you want to spend your idle time, keeping in mind that you won't have any online shopping available (at least for a while!).
Another aspect of your pre-departure training might include some time in a neutral buoyancy tank, like the one used to train NASA astronauts for their time on the Space Station. These aren't widely available to the public yet, but there's no reason that couldn't change:
If you can't get access to a full spacesuit-in-a-pool experience, the next best thing might be to learn to SCUBA dive. It's an awesome experience on its own, and if you approach it in the right way, it can also provide a preview for what it's like to be in zero-G. It's not exactly the same, of course, since you can swim while floating in water, but not while floating in air. For the latter, there's nothing to grab onto or push against.
Getting There
The next level up from Deck B in the previous issue, is Deck C. This is another combined cabin and launch couch deck, reconfigurable from one to the other, as with Deck B. The sketch below shows the cabin configuration, with walls replacing the crash couches, forming 25 cabins:
The cabins are small, with two people assigned to each. Most have windows. You will be able to stow your carry-on gear in the ceiling, and sleep on the walls, floor or ceiling. One nice thing about sleeping in zero-G is that there's no pressure pushing on your body, hence no risk of sore spots or the like from sleeping on a too-thin mattress. Instead, you can just stretch out and park yourself anywhere you want in your cabin. There will be straps of some kind to keep you from floating around and banging into your cabin-mate or other things.
Expect to sleep and eat in shifts. A shift-based approach will help make the ship feel less crowded. With 8-hour shifts, a third of the passengers would be asleep or in their cabins at any one time.
Here's what a typical sleeping situation looks like on ISS. The green fabric on the right side is a sleeping bag, arranged vertically:
There are also another couple of bathrooms on this deck, and passageways in the middle to go down to Deck B or up to Deck D.
What will your communications options be like while in transit? Will you be able to communicate with friends and family back home? Yes. This will be a very important feature for Starship. Due to the speed of light delays, though, using the Internet won't be the same on Starship as it is on Earth. Instead of Skype or Zoom, the way it will work is that you will record your half of a conversation, and send it to your friends. Similarly, you will be able to receive and play audio and video they send you. It's just that there will be a delay on each end between sending and receiving. Relatively short delays right after departure, increasing to at least 3 minutes once you arrive at Mars, up to a maximum of about 22 minutes when Earth and Mars are at their most distant. On average, once you're there, the delay will be about 12.5 minutes.
Living There
Here's a photo taken by Curiosity of a metallic meteorite on Mars, along with nearby surface material. It's interesting to see how fine-grained the sand can be; it's close to being more like powder than sand. Meteorites similar to this are likely to have significant commercial value on Earth for quite a while after colonization on Mars begins. I'm expecting it to be possible to make a pretty good living collecting things like this and selling them when you return to Earth (they may well be magnetic). I'm hoping early explorers also find good sources of interesting gems. Maybe polish them on Mars to minimize their weight, before bringing them back. Even simple tumbled rocks from Mars would be pretty cool.
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