Delivery of Martian soil
For the delivery of soil and rock samples from Mars, a target complex
of the following composition is proposed:
- lander (SA);
- assembly compartment with orientation unit;
- the orbiter.
The lander contains a heat shield, a landing platform, a take-off module, a rover with a sampling device, and a return container.
The aggregate compartment provides the orientation of the complex and corrections of its trajectory on the way to Mars, as well as the orientation of the spacecraft before entering the atmosphere.
The orbiter is equipped with an ERPS, equipment for searching for the returned container and a mechanism for capturing it.
The flight plan consists of several stages:
• RN " Angara
5-VHF " outputs a complex with a mass of up to 27 tons to the OS.
• The VHF refuels, launches and accelerates the vehicle, providing a characteristic
speed of about 3800 m / s, which is enough to put it on a trajectory to Mars
even if the planets are not in the most favorable position.
• With the help of the aggregate compartment, trajectory corrections are made to ensure the approach to
To Mars with the specified trajectory parameters.
• The complex enters the atmosphere along a hyperbolic trajectory and decelerates, losing ~650-700 m / s of speed, after which it ends up in a highly elliptical orbit.
• There is a separation of the orbiter, which turns the SB and with the help
of a small pulse in the apocenter is transferred to a stable orbit.
• The lander enters the atmosphere and makes a soft landing. During the descent
the heat shield is dropped and the parachute system is activated,
the final stage is provided by the soft landing jet engines.
• The rover leaves the SA, takes rock samples and puts them in a container.
• The take-off module with the return container takes off and enters a highly elliptical
orbit or (at a low speed) - on the departure trajectory.
• The orbiter finds the take-off module, approaches it, retrieves
the sample container, and transports it to Earth using the ERDU.
• The orbiter is approaching the Earth and entering a high circular orbit.
After completing all the steps, the task can be considered completed. However, the rock samples
were not delivered to Earth. How this is done depends
on the biological safety requirements. It is possible to send a special
interceptor device, or the container will be carefully transferred to
a highly elliptical orbit, which will eventually
be converted into a circular one by atmospheric braking, and will be picked up on it. It
was the biological safety considerations that determined the type of propulsion
system of the orbiter – ERDU, although it could easily cope with the task of returning
installation on liquid chemical components. At the same time, the mission can be successful
even without an orbiter, especially with a two-stage take-off
module design.
The mass distribution of the components of the complex will strongly depend on the mass perfection of the take-off module. So, with a starting mass of 10 tons (which is feasible) and the ratio
of the mass of the structure with the remaining components to the mass of the fuel used is 1:10
the weight of the filled container will be 800 kg, at 1:6-less than 250 kg.
(characteristic speed – 6500 m / s). With the worst perfection, it makes sense
to consider a two-step option.
Manned expedition to Mars
In order to send a full-fledged expedition of 6 people to Mars and return back with the help of the LRE
, you will need to assemble a Martian ship with
an initial mass of 800 to 1200 tons in low-Earth orbit. Accompanying such a large mass
of grandiose orbital construction can result in excessive costs,
so all the recent Martian projects are based on promising
technologies. The main ones are the production of fuel components from local raw materials and high-efficiency low-thrust engines.
Their use allows you to reduce
the initial mass of the ship is 2-2. 5 times,and until they are worked out,
it is premature to talk about the final choice of the flight method. In this regard
, the Phobos-Grunt mission is of crucial importance, which could assess
the satellite's dust reserves and answer the question: is it possible to obtain
oxygen and other fuel components on-site from the Phobosian soil.
The SV system, which has the structure we propose, will be useful for a Martian
expedition, regardless of whether promising technologies are applied or
not. When using it, the scenario of a Martian expedition will look like this:
Creation of a Martian orbital base
Early delivery to the Martian orbit of those goods that are not
required on the Martian ship on the way to Mars, will avoid unnecessary
overstrain at the start of the expedition and increase its reliability. Orbital base
(OB) may be collected gradually, over a period of 10 years or more, and the
cargo on it must be long-lasting. These can be, first of all,
fuel components, water, some food products, various tools and
accessories. It is reasonable to place reserve energy capacities on the base as well.
The completed base should also serve as a crew shelter.
If you use the Angara 5 – VHF launch vehicle, then with refueling at the UGC in one launch to
Mars is provided with the removal of a block weighing up to 27 tons. Minus the means of entering
the Martian orbit (braking remote control, heat shield), its useful mass
should be about 20 tons. In total, you need to send at least 7-8 blocks, the assembly
of the preliminary configuration is assumed to be automatic. If
the Martian ship contains an ERDA, then at least a few units
should also be equipped with an ERDA that is technologically unified with the ship's.
The latter, most likely, will be typeset, consisting of several dozen
elementary engines. Then it will not be difficult to create a low-power installation
for the units to test and gain experience in its operation in real conditions,
and then have a source of spare parts for the main ERDU on hand. The electric
power of the unit with an ERDU should be at least 40-50 kW.
It is possible to increase the mass of the OB unit without losing the delivery efficiency if
it is loaded on the UGC with fuel components (liquid oxygen and liquid methane) or
water. Then the NG delivered to the UGC must contain a certain number of accelerators,
as well as tanks. At the UGC, the tanks are filled with fuel components or water, and
the accelerators are installed on the VHF and then participate in the acceleration of the block at
the initial stage of removal. The mass layout of such a complex can be
as follows:
Mass of accelerators 22 tons;
including 20 tons of fuel.
Specific impulse 3200 N * s/m.
Weight PG 39 t;
including-filled liquid cargo of 30 tons.
Apparently, it will not be possible to get more from this method.
The Martian ship
The Martian ship is assembled in an extremely high orbit, more precisely, on a highly disturbed trajectory near the boundary of the Earth's sphere of action. The transition to such a trajectory should require a minimum momentum at the apogee of the elliptical orbit, and the prevention of departure from the Earth's sphere of action-a small cost of the characteristic velocity. The need to build a ship away from Earth is caused by two reasons:
The assembly of the ship in remote orbit will be carried out in conditions of vulnerability to galactic cosmic radiation, so operations involving humans should be kept to a minimum. The main stage of the assembly is supposed to be carried out without the presence of the crew on board. This requirement will be difficult to meet if the ship is equipped with a powerful ERDU that uses solar energy. The deployment of the latter will be difficult to implement without the work of astronauts in outer space. Apparently, in the case under consideration, ERD will have to completely assemble it in low orbit, and then drive it under its own power to the assembly site.
Start of the expedition
The start of the expedition depends on the type of main engine and can be one of two options:
To transfer the ship to the flight path to Mars without diving into the gravity well, an increase in the characteristic speed of ~3 km/s will be required, but when using low-thrust engines, such a dive will not lead to a significant reduction in it. However, a deep dive to the Ground is preferable to a long-distance flight of the crew to the ship. First of all, this will reduce the radiation hazard, since the MK will be much better protected than the vehicle on which the crew will reach the ship. It should also be taken into account that forecasts of solar activity for 10-15 days required for the flight, even if they are possible, will not help in any way because it is impossible to postpone the start date for more than two or three days. Secondly, the flight to the MK can be made with the help of a simple and used vehicle, and the crew on duty can also be returned to Earth on it. With this scheme of crew delivery, all the components of the MC will be assembled in advance into a complex and tested, and the problems are identified and eliminated. If the crew of the ship does not reach the ship, the possibility of landing the backup crew "in pursuit" remains".
Expedition using the LRE
Next, consider a ship that uses an LRE in conditions of a favorable location of the planets. The estimated mass of the ship will be about 360 tons, which is enough in the presence of a Martian OB. To assemble it, you will need up to 13 launches of the Angara 5 launch vehicle – VHF" or up to 16 launches of the A4-VHF PH with reusable side modules, as well as 2 more launches of the PH with oxygen-methane blocks with the following characteristics:
Block mass 55,75 tons;
fuel mass 50,68 tons;
payload mass (ÐÍ – «Àíãàðà 5») 24,1 tons;
specific impulse 3620 N·s / m.
The assembled ship will include two methane blocks with fuel that
is delivered separately. When delivering fuel in the same way as proposed
above for the Martian OB, one VHF is able to bring up to 50 tons of NG
containing up to 45 tons of fuel to the assembly site. One of the blocks is used twice – at the very
beginning of the expedition, it pushes the ship from a distant circular near-Earth orbit to
an elliptical one, and then accelerates it near the Earth and puts it on
a flight path to Mars, providing a characteristic speed of at least 500 m/s. After
the output block is not discarded, being kept in reserve. The second unit is used
to decelerate and bring the ship into Martian orbit. Later, one of the blocks
refuels on the OB and puts the ship on a return trajectory.
To ensure the assembly of the ship, it will be necessary to deliver at least
750 tons of water to the UGC and process it. This is 100 MKT flights with a load capacity of 7.5 tons (or more than 200
MKT flights with a load capacity of 3.5 tons) and 0.5 MW of electric power
for two years. Such a power of the SB is quite large, in addition, there may
be a situation in which after the launch of the Martian ship, the electrical
power of the UGC will not be in demand. Therefore, it makes sense to use
the power plant of the Martian ship to increase the power of the UGC.
If the cost of launching the Angara 5 – VHF launch vehicle is $80 million, and the cost of a kilogram
of oxygen-hydrogen fuel at the UGC is half the cost of launching
a kilogram of NG, then the cost of ensuring the launch of the spacecraft into Martian orbit
by means of launch vehicles will be about $3 billion.
The scheme of the rest of the Martian expedition contains nothing new and can be
borrowed from other projects. The novelty may come if
mining water is found on Martian satellites, which is unlikely. Then
it makes sense to consider the possibility of producing oxygen-hydrogen fuel
on the ship and using VHF.
Despite the fact that the Martian ship at launch contains more than 100 tons
of oxygen-methane fuel and there is still a reserve on the Martian surface, the main
energy of the expedition is provided by VHF, using high-efficiency
oxygen-hydrogen fuel. A significant contribution to the energy sector will also be made by the electric capacity of the UGC, from which 1 GW·year of energy will be required only to provide the MK itself.
The choice of oxygen-methane fuel is explained,
on the one hand, by its acceptable physical and energy
characteristics, and, on the other hand, by its cheapness in orbit and the readiness
of its use infrastructure (UGC). Provided that it is reliably shielded from
the Sun, it can be stored for a long time at all stages of the expedition: in the orbit
of the spacecraft assembly, on the interplanetary route and in the highly elliptical Martian
orbit, while storing liquid hydrogen (boiling point – 22°K) in
a multi-month autonomous flight is expensive and risky. In the future, methane
fuel will be easy to produce in space if raw materials are available. If
regular flights are required, and the energy properties of methane are
insufficient, then it is possible to increase them by using additives.
Òàê, èñïîëüçîâàíèå âìåñòî ìåòàíà ìåòàí-äèáîðàíîâîé ñìåñè ïîçâîëèò óâåëè÷èòü ÓÈ
äî 4000 Í·ñ/ì, íî òàêîå òîïëèâî âñòðåòèò ýêîëîãè÷åñêèå ïðåïÿòñòâèÿ ïðè
îòðàáîòêå è ïîòðåáóåò óñëîæíåíèÿ ñõåìû äâèãàòåëÿ. Ôàêòè÷åñêè, ïîòðåáóåòñÿ
òð¸õêîìïîíåíòíûé ÆÐÄ, òðåòèé êîìïîíåíò êîòîðîãî áóäåò îáåñïå÷èâàòü ðàáîòó
ãàçîãåíåðàòîðà. Èì ìîæåò áûòü ÷èñòûé ìåòàí èëè ïåðåêèñü âîäîðîäà.
Exploration of distant planets
Some missions to other planets require such a high characteristic
speed that they are carried out according to previously used schemes using
The LRE will lead to an unacceptable increase in the launch mass of the device. Therefore
, projects for the use of efficient low-thrust engines are being developed.
Individual samples of such engines have already shown a specific impulse of 30000 in flight
N·s / m, and in the future will be able to provide up to 60,000 N·s/m. As a source
energy is assumed to be solar panels or a nuclear reactor. The reverse side
the use of such an engine is a low acceleration, as a result of which
many months are spent on gaining a significant speed. All known projects
of such vehicles provide for the beginning of movement from low Earth orbit.
Despite the large specific impulse of the remote control, this method of movement has major disadvantages.
These disadvantages are easily eliminated if you tell the device the initial acceleration of 3-4 km/s. When using the OSS and refueling the last stage, the launch cost will increase 1-6. 2 times, which is not significant for such missions. But, on the other hand, the time to reach the target will be significantly reduced and the reserve of the characteristic speed will increase, or the spacecraft can be reloaded with equipment. An example of such a project is the apparatus for studying the Jupiter moon Europa(project JUMÎ (NASA) and similar studies carried out by a number of Russian organizations. The projects are based on the use of ion engines and an onboard nuclear power plant. The table below shows data on two flight options for such a device. The first involves putting the spacecraft into a radiation-safe orbit at an altitude of 800 km with the help of the Angara 5 launch vehicle and further acceleration with low thrust (ñì. «Íîâîñòè êîñìîíàâòèêè», ¹ 1, 2005 ã.). In the second device, an initial impulse of 4.43 km/s is given, the launch is carried out from the base orbit of the UGC (H=450 km). The starting masses of the vehicles of both variants are equal (for the convenience of comparing the possibilities), acceleration in the second variant can be performed by the last stage of the Angara 5 PH, which does not use hydrogen.
|
|
Using only the ERDU |
Additional overclocking with refueling of RB on OZK |
|
Power of the nuclear power plant, kW |
100 |
100 |
|
Òÿãà, ãñ |
329 |
329 |
|
Specific thrust, s |
4500 |
4500 |
|
Initial mass of the spacecraft, kg |
21450 (Í=800 êì) |
21450 (Í=450 km) |
|
Characteristic speed in the Earth's sphere of action, km / s |
7,0 |
4,43 |
|
Characteristic speed achieved with the ERDU, km / s |
35,4 |
23,0 |
|
Final weight, kg |
9622 |
12740 |
|
Flight time, days/years |
2791/7,65 |
< 2000/5,5 |
|
Weight of scientific equipment, kg |
1272 |
4390 |
|
Additional load, kg |
- |
3118 |
The initial acceleration from low orbit significantly reduces the flight time and the operation time of the ERDU, and allows you to significantly increase the mass of the delivered scientific equipment. It is likely that only the advantage of reducing the flight time will cover the ~10% increase in the cost of the project due to the use of UGC capabilities.