Ares III for LEO, Ares IV for the Moon. None of this DIRECT nonsense, you see...
Quote from: William Barton on 07/24/2009 08:35 pmAres III for LEO, Ares IV for the Moon. None of this DIRECT nonsense, you see...Let's hope they don't try to abbreviate Shuttle Inline Transport-1 and Shuttle Inline Transport-2Modify: or transit
These are all good points. But it is worth pointing out that a number of other proposed missions get stranded at the study phase because they do not fit on an existing launch vehicle. Mars and Venus sample return are good examples of this. Mercury landers also fall into this category. And that is just planetary. We haven't even started talking big telescopes yet...
... These are all really high energy, high weight, because the basic task is to throw a giant mass of hydrazine out there, with some instrumentation going along for the ride. The lunar orbiters are barely possible with Atlas V 551 or Ariane V ECA or even (at Flagship cost level) DIVH/AVH. But the landers may not be, and the Europa submarine is probably the single greatest mission we can hope for in our lifetime (apart from optical interferometer space telescopes, for pretty much the same reason!)
And no, the missions won't get cheaper because they can have more mass. The costs come from the complexity, not the limited mass budget.
So a HLV could significantly reduce the cost of flagship missions.
Quote from: rklaehn on 07/26/2009 09:13 amSo a HLV could significantly reduce the cost of flagship missions. Costs for the launcher are just a fraction of a flagship mission. Even building the mission hardware is just a fraction. Most costs are incurred for development, management and planning and operations. An HLV instead of an Delta-IV H or an Atlas 551 won't decrease those costs. It's not going to be cheaper to design and build a 50mt spacecraft compared to a 7mt spacecraft, no matter what you do and which approach you take.
Quote from: rklaehn on 07/26/2009 09:13 amSo a HLV could significantly reduce the cost of flagship missions. Costs for the launcher are just a fraction of a flagship mission.
Most costs are incurred for development, management and planning and operations. An HLV instead of an Delta-IV H or an Atlas 551 won't decrease those costs.
It's not going to be cheaper to design and build a 50mt spacecraft compared to a 7mt spacecraft, no matter what you do and which approach you take.
1) So a HLV could significantly reduce the cost of flagship missions.2) But due to the aerospace culture and politics of publicly funded projects, it probably won't happen.
No, but if you overspend a billion dollars folding a 6.5 meter mirror into a 5 mirror fairing, an 8.4m fairing is an easy way to simplify the mission.
And that is exactly why spending more on a launcher to reduce all the other costs might make sense.
1) Operations can be simplified and shortened by using direct trajectories instead of complex trajectories with gravity assists. Avoiding a gravity assist means two years less you have to keep the team together.2) Surely that is worth a lot of money.
OK-1) A couple of pages back, there was a graphic of a ET with 4 SRBs strapped to it. The follow-up mentioned that while scary-capable, that beast was also HEAVY- as in crack-the floor, break-the-back-of-the=crawler and dig-ruts-in-the-crawler-way HEAVY. Well- what about using 3 SRBs, or adding two (or more) of the midget-solids that Delta uses? Any benefit there without pushing things beyond their Young's Modulus?
If you really wanted to lift 200 tons or more in one vehicle while still using existing facilities, you would have to go kerolox. One could fit a 12 meter kerolox booster inside the VAB and it stll be light enough to transverse the crawlerway. No solids since they are very heavy. The Saturn V could have been upgraded by improving the existing F-1 engines to 2.2 million lbs of thrust, and the J-2 upper stages from 200k lbs each to the J-2X for about 275k lbs each. This would have gotten you into the 150-175 ton range. Modern construction methods, CC boosters, etc, and you can get 200 tons. It would require today a clean-sheet design. Do we have the time or money or will to do this?
* Jovian *lunar* orbiters: Europa, Ganymede. * Saturnian *lunar* orbiter: Titan * Neptune orbiter * Europa lander. Europa *submarine*! * Titan lander These are all really high energy, high weight, because the basic task is to throw a giant mass of hydrazine out there, with some instrumentation going along for the ride. The lunar orbiters are barely possible with Atlas V 551 or Ariane V ECA or even (at Flagship cost level) DIVH/AVH. But the landers may not be, and the Europa submarine is probably the single greatest mission we can hope for in our lifetime (apart from optical interferometer space telescopes, for pretty much the same reason!) Jupiter 130 could really change that.
Quote1) Operations can be simplified and shortened by using direct trajectories instead of complex trajectories with gravity assists. Avoiding a gravity assist means two years less you have to keep the team together.2) Surely that is worth a lot of money.1) You have to decide: Heavier spacecraft or faster trajectories. The first won't save you cost, the latter increases arrival speed (and therefore delta v, and therefore mass, larger tanks, longer burning engines ... or more complicated EDL.)
I vote for a Sedna orbiter, with HIRISE sized telescope. Seeing the first known Oort cloud object up close?!! YES!!!
And this is wrong too. Larger tanks means heavier spacecraft means different attitude control, thermal, structure ...
Quote1) So a HLV could significantly reduce the cost of flagship missions.2) But due to the aerospace culture and politics of publicly funded projects, it probably won't happen.1) You are wrong.2) Has nothing to do with culture and politics. The complexity does not come from the limited mass budget, but from the tasks the spacecraft has to perform.If it were otherwise, Pegasus, Taurus, Delta II ... all would be out of business and only the biggest launch vehicle would be used, even for a SMEX explorer. Heck, for a small satellite Delta IVH is heavy lift, yet they don't use it.
Quote1) Operations can be simplified and shortened by using direct trajectories instead of complex trajectories with gravity assists. Avoiding a gravity assist means two years less you have to keep the team together.2) Surely that is worth a lot of money.1) You have to decide: Heavier spacecraft or faster trajectories.
The first won't save you cost,
the latter increases arrival speed (and therefore delta v, and therefore mass, larger tanks, longer burning engines ... or more complicated EDL.)
2) Much less than you think. Spacecraft can sleep.
SMD won't use HLV. They can't afford it. They can barely afford a new mission here and there. They are looking for a Delta II replacement.