New answers tagged

1

For the latest TLES you can use Celestrak; 1, 2, 3 and there are some collections of some historical (but not recent) TLEs as well. You can access a huge collection of historical TLEs in Space-Track after you register and read the rules. See this answer for more on that. When I first started I also though I'd have to scrape them from websites! See also ...


1

The question here is not so much about pressure fed engines as about thrust. If you need to land 240 tonnes of space craft on the moon you need to overcome at least the force of lunar gravity on that mass with engine thrust or it stops being a landing. So there is a fixed lower amount of thrust needed to land a given craft on a given body and it scales with ...


4

It's a valid question. The Starlinks would require larger tanks but we're still only talking about a few percent of their 227 kg mass because they use high solar-electric propulsion rather than conventional rockets. I estimated about 2.3 kg of liquid krypton for the lower orbiting Starlink satellites in this answer. That included orbit raising from 445 to ...


1

Somebody on reddit did an excellent chart of the Falcon 9's landing accuracy: [source] While these landing positions are probably just approximate, I think it is reasonable to assume that the answer to the question is: yes, Falcon 9 and Heavy boosters need landing legs because they cannot land back onto their launch mounts.


0

Right now Starship and it Superheavy booster are both open design. Current plan is for 35 engines on 1st stage, 6 on 2st stage, 150ton to LEO ascend payload, dry mass 85t, return to Earth payload 50t. All of this could change during rocket development, because of technological challenges, but also money which will have SpaceX available during development ...


6

From a driving dynamics point of view, there aren't any immediate concerns that lead me to think it won't work at all. However, that said, nobody has much experience driving vehicles at any fast speeds on the Moon or Mars. The Curiosity rover travels at a maximum of 1.5 meters per minute and the Lunar Roving Vehicle hit top speeds of 13 kilometers per hour. ...


3

I recognize that this is a highly unlikely situation, but a couple things to consider: Tesla vehicles have a sophisticated thermal control system for the battery. Now, battery recharge cycles/lifetime may not be as big a concern on Mars as they are for Terran consumers, but given Martian temperatures, a lot of the battery charge might be expended just ...


5

The liquid oxygen was delivered from a remote location (likely Hawaii). The source doesn't state but it would have to be by ship. You might recall that the very first Falcon 1 launch attempt was scrubbed because a LOX valve opened in the storage facility and blew off too much LOX. Then Based on the ensuing discussion after the abort, the team expects ...


5

The most sensible and specific account I've come across is as follows: RUPTURE UPDATE: Through back channels it has been revealed that MK1 suffered an accidental overpressure to failure. Fuel and oxidizer would typically be loaded to 3 Bar or 43.5 psi— for densification purposes and flightworthy tanks may be tested to 1.5-2x that value for single time ...


0

The simple answer, as already stated by others, is that small rockets do not align with Musk's goals of putting people on Mars. Additionally, Spacex already have a small (OK, medium sized) launcher in the form of Falcon 9. They claim that Starship + Falcon Superheavy will be able to undercut it. One possiblity I wouldn't disregard (if Spacex chose do go ...


3

The first batch of ~60 Starlink satellites was a scrappy lot. Below is a plot from What are these four “debris” objects along with the Starlink satellites? about two weeks and then six weeks after launch, showing that they took substantially different paths to reach their ultimate target orbit. Ignoring time zones, the photo was taken on 18-Nov-2019, a ...


4

The streaks are due to extended exposures. From a non-rotating earth, the satellites (this close to release) would follow each other in the same arc across the sky. That arc is the projection of the orbit and never changes. From a rotating earth, that arc is not always in the same place: the earth rotates under it. So a satellite is moving along an arc ...


10

Basically they are not quite in the same plane. As a satellite raises or lowers, not only does it change the relative position within an orbital plane, it also will slowly shift the longitude of the ascending node with respect to the other satellites, called the "Nodal Precession". In fact, this happens every day. There is a lot in this, but the bottom line ...


7

Similar to how a small plane can't really carry any people around the world, but a larger plane can, it turns out there are challenges to making really small rockets. These are magnified when you take in to account full reusability. It turns out that Starship is about the smallest spacecraft that makes sense for a fully reusable spacecraft. A few things to ...


8

There was some talk of modifying Falcon 9's second stage to give it full reusability in November of 2018. The idea was that a reusable second stage would be used to test out Starship technologies. This effort was scrapped 10 days later in favor of accelerating development on the current stainless steel design of starship. The superheavy/starship ...


43

There are several compelling engineering and design reasons why a bigger spaceship makes sense and several reasons why making a mini-starship does not make sense for SpaceX specifically (and their vision). First and foremost, Elon Musk has made it clear that his goal for the company and the future isn't to provide cheap satellite launch capabilities, it's ...


5

I posted this a while back on Twitter (@rocketscient1st) when the first Starlink was launched: Conducted a simple analysis on a complete Starlink Phase 1 constellation. 1584 satellites: 24 planes with 66 satellites each. 53° inclination; 550 km altitude. I assumed the relative phasing as I have no direct information. I do not know the absolute magnitude of ...


1

I believe these are the flaps that open and close to reveal the openings for the SuperDracos. The SuperDracos allow Dragon 2 to separate from the rocket during aborts. I think they swivel so the ones on the side go inward and the ones on top drop down to cover the holes made by the parts swiveling inwards. https://www.teslarati.com/spacex-fires-redesigned-...


11

The answer, like many things in the business world, revolve around money and time. Building/developing a satellite, let alone a satellite assembly line capable of pumping out thousands of satellites, is not cheap and not quick. Even if you had an infinite budget, you can only hire so many engineers until you start seeing diminishing returns. SpaceX has made ...


3

They have said that they will mitigate the reflectivity of the satellites in future batches and that the 1.0 launch, Nov 11 they did not complete that for this batch. In the December 2019 launch they plan to test darkening one of the satellites to see if it meets their needs. (chief operating officer Gwynne) Shotwell said the next batch has one satellite ...


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