The cost of large launch vehicles is so high that a depot able to hold the propellant lifted by two or more medium-sized launch vehicles may be cost effective and support more payload mass on beyond-Earth orbit trajectories.
22.
The ultimate goal of optimal staging is to maximize the payload ratio ( see ratios under performance ), meaning the largest amount of payload is carried up to the required burnout velocity using the least amount of non-payload mass, which comprises everything else.
23.
Again, it is helpful for understanding to emphasize that large single warheads are seldom a part of today's arsenals, since smaller MIRV warheads spread out over a pancake-shaped destructive area, are far more destructive for a given total yield, or unit of payload mass.
24.
The flight was contracted with a payload mass that is very small relative to the rocket's capability, at a discounted rate because it was a technology demonstration mission for SpaceX, approximately 20 % of the normal published price for SpaceX Falcon 9 LEO missions.
25.
The combination of high fuel efficiency and low-mass engines permits a single-stage-to-orbit ( SSTO ) approach, with air-breathing to Mach 5.14 + at altitude, and with the vehicle reaching orbit with more payload mass per take-off mass than just about any non-nuclear launch vehicle ever proposed.
26.
Cryogenic satellites that require liquid helium ( LHe, T H " 4 K ) temperatures in near-Earth orbit are typically exposed to a large heat load from the Earth, and consequently entail large usage of LHe coolant, which then tends to dominate the total payload mass and limits mission life.
27.
On 2 December 2014, ESA decided to stop funding the development of Ariane 5 ME and instead focus on Ariane 6 which should have a lower cost per launch and allow more flexibility in the payloads ( using two or four P120C solid boosters depending on total payload mass ).
28.
An additional expression for the overall structural mass fraction can be found by noting that the payload mass fraction \ left ( \ frac { m _ \ text { pl } } { m _ i } \ right ), propellant mass fraction and structural mass fraction sum to one:
29.
They indicated that details would be forthcoming in " one to three years " and that the large engine was intended for a new SpaceX rocket, using multiple of these large engines, that would notionally launch payload masses of the order of to low Earth orbit, exceeding the payload mass capability of the NASA Space Launch System.
30.
They indicated that details would be forthcoming in " one to three years " and that the large engine was intended for a new SpaceX rocket, using multiple of these large engines, that would notionally launch payload masses of the order of to low Earth orbit, exceeding the payload mass capability of the NASA Space Launch System.
