Posts by Vulch 659 publicly visible posts • joined 28 May 2008
The 2000 figure for miniumum viabiloity is purely for genetics. It assumes you've got breathable atmosphere, water, and edible plants and animals wandering around. If you need to make sure the air purifiers keep working, and the pressurised greenhouses stay well lit, and there are hospitals to treat whatever ailments occur, then the million figure is what is required.
If it wasn't for the minor detail of the atmosphere, the last couple (at least) of Starship flights would have been orbital as calculated by Jonathan McDowell although the perigee would have been between 3 and 5km. Relighting a raptor in space has been done, although so far to give the ship a bit of extra boost rather than bringing it down. According to His Muskiness, they want to do two repeats of that flight profile (previous relights were Raptor 2, next several flights are Raptor 3) before going for a proper orbit and a ship catch back in Texas.
Err, no. BBC staff were mostly members of the ABS and the same agreement covered everyone. Two or three (it's been a while, I forget which) repeats were part of the Equity contract and there wasn't a time limit that I ever encountered. Further repeats could be made, but everyone appearing had to give permission and be paid their full fee again. Extras in particular would come and go, and generally it wasn't considered worth the expense to try and contact everyone. This changed with the advent of home video and the Equity contract no longer allowed vetoes (so The Professionals returned to ITV screens) and an escrow fund was created to hold payments for those who had dropped out of contact.
[Ex BBC-VT]
Prestige drama would generally use new tapes, more routine stuff would use pre-loved tapes though we'd check for drop out when doing the line-up and it was not uncommon to condem a tape and ask the library for a different one. At the bottom of the heap was "Good enough for sport".
[Ex BBC-VT, late Tom Baker, early Peter Davison era]
Much smaller craft. The Orion is about the same mass as an Apollo CSM but carries a lot less fuel, it can't get itself into low Lunar orbit whereas Apollo could put the CSM and docked Lunar Module there. HLS is 8-10 times the mass of the Lunar Module and even by pessimistic estimates could carry a couple of LMs as cargo.
Satellites generally share the ground stations so get a timeslot depending on the amount of data expected. They'll either get told when their next slot is expected to be so they can have a high gain aerial pointing the right way at the right time, or be passively listening for the equivalent call of "Oi! TESS! Data, now!". Telemetry would be sent during the timeslot, not continuously. If the battery holds enough for 48 hours operation but the timeslot is once a week you probably won't spot the decline soon enough.
Even if the HLS is ready in time, it's entirely possible the suits for the Lunar surface EVAs won't be. In joined up planning, each crew memebr heading for the surface of the moon will need three suits, one to use in the Orion, another for the HLS and a third to go for a walk outside. The Orion and HLS suits exist, the surface suit is being produced by Axiom who are behind schedule and reported to be having cash flow problems.
Power supply and cooling can be limiting for land based laser defence systems. The article mentions 50kW so you need a generator that will provide that, and a fair bit of it will land up as waste heat that you need to get rid of. Ships have nice big engines with generators attached and sit on a relatively cool heatsink, or the ocean as it's sometimes termed. The army version mentioned is a fair bit less powerful as everything has to fit in an AFV chassis or two.
Nah, he's got a five letter first name. There's a much closer disguised 4-4 who has already been dropping bits of rockets on people...
Around the Falklands event it was noticed that a lot of the photos of troops yomping across the islands showed non-issue kit being carried and worn. Turned out that a lot of units would give new recruits a loan from the slush fund and a shopping list with which shops they should visit. Issue kit was for inspections, the bought stuff for actual use.
Their first mission failed when the landing trajectory passed over a cliff and the altitude reading suddenly increased a lot. The onboard computer decided it must be broken and so ignored it, resulting in the lander coming to a perfect hover with the minor flaw that it was still 5km above the ground...
They were already a bit short of panellists as a lot of the usual attendees who would do a couple of panel sessions have decided not to risk travelling to the USA for the forseeable future. A number of people who did get through the vetting process have dropped out since and several also requested a refund of their membership.
People who know stuff are suggesting the reflight will be cargo only and paid for by NASA (so letting Boeing off the financial hook) due to the next Cygnus freighter having been dropped or otherwise bent out of shape sufficiently to make it currently unflyable. That leaves a big hole in the resupply schedule, so an extra cargo flight is more use than a crew exchange.
With a bit more blaming Boeing, apparently the new Crew Dragon wasn't intended to fly until August as the February crew rotation was expected to be the first Starliner operational flight. The new Dragon isn't so much delayed as not possible to finish it safely six months early.
There's still propellant on board (and quite a bit this time judging from the frost lines on the dangling booster) and the booster is quite warm so some of it is boiling off. They vent to stop it going pop through the engines and through the QD plate. It's the QD plate was doing dragon impressions this time although it's not clear what was igniting it. It has dedicated vent lines for use during fuelling so once they are able to put the booster straight back on the launch mount they will be able to use those rather than venting to atmosphere.
It could be something as simple as getting the launch done before the work day starts in the nearby industrial area. That area has to be evacuated when SpaceX is due to land a booster back at LZ-1 or LZ-2 which are just north of the BO pad, so it's likely that it would need to be evacuated for a New Glenn launch which has the potential for a much bigger boom than would happen with a nearly empty Falcon 9 booster.
Curemtly available on iPlayer for the next 11 months.
Other than switching the provisional first operational Starliner flight to SpaceX, NASA has yet to announce what work will be needed to get Starliner certified. They may well require another test flight, probably uncrewed, although it may be part funded as a cargo run. It's another looming hole in Boeing's finances.
Indeed. Took NASA a very long time to work out there were only a couple of photos of Neil Armstrong on the moon because the two suits were essentially identical. Later missions used the red stripe for the commander, Shuttle EVAs assigned the red stripe to one of the astronauts leaving the second one plain. On a few occasions there were three astronauts on EVA and the third wore a blue stripe on their suit.
Falcon 9 boosters appear to spend less than a fortnight being inspected and refurbished after a flight, during a launch stream a while ago it was mentioned that particular booster had gone through the process in nine days. There is absolutely no need to strip and rebuild engines between flights, even the Shuttle main engines didn't need it although inertia meant they generally were. SpaceX already have a lot (as in hundreds of reflights) of experience in reusing rockets.
Originally the landings were described as "experimental" in the FAA licence applications so if they didn't work that was still in accordance with the licence. After 267 straight landings they're no longer experimental so a crash like this is outside the licence conditions so must be investigated. On the plus side, reliable sources have said the cause is trivial to fix and the shutdown may be even shorter than the one after the second stage failure.
Not really. For the Dragon the only things carried by the trunk are solar panels and radiators, everything else is in the capsule. That's in stark contrast to the Starliner and Orion capsules which do have a traditional service module containing a lot of the (very expensive) equipment required. eg Starliner is having trouble with the thrusters on its service module, there aren't any on the Dragon trunk.
There have been notes that the minimum detectable level for mercury in the tests used is 0.113 ug/l and it is standard to list negligible mercury concentration as "> .113" in reports. This could mean it's just a typo no-one caught until now, and it's also somewhat puzzling where that amount of mercury could be coming from if it isn't a typo.
The location in question is the Michoud Assembly Facility which is an Apollo era legacy site. Under NASA ownership it was used to manufacture the Saturn 1 and 1B first stages, followed by the Saturn V S-1C first stage, and then rejigged for the Shuttle ET and now SLS. Administratively it's part of Marshall SFC with part being hired out to Boeing and other bits to LockMart for building Orion capsules.
The various docking ports are also of three different types. The Cygnus freighter that arrived recently uses a CBM port, Soyuz and Progress craft use the Russian style docking ports. Dragons and Starliners use IDA ports and there are, as has been said repeatedly, only two of those on the ISS. Crew 9 cannot dock with the ISS until either the Crew 8 Dragon or the Starliner leave and free up an IDA port.
SpaceX Crew 9 was due to launch this weekend, now pushed back to the 18th due to the recent second stage failure. NASA would like Starliner gone by then as it's tying up a docking port and, if it's still there, it means Crew 8 have to leave before Crew 9 launches and they really like having both crews on the station for a week to do a proper handover. Additionally if Starliner is deemed unsafe then Crew 9 will launch with just the commander and copilot to free the other two seats for Starliner crew return. That has research time implications as the mission specialists have been trained on the experiments due to be run during their stay, and also political implications as one of the crew that would miss the flight is a Russian Cosmonaut which would leave that side of the station understaffed.
