The Gen1 Enterprise will serve as a spaceport for spacecrafts that leave the Enterprise and land on Earth, the moon, or Mars. So rather than develop a different landing craft for each case, it is desirable to develop one craft that can handle all three destinations. This is called the Universal Lander.
The Universal Lander can depart from the Enterprise and land on the Earth, the moon, or Mars – but it can also launch from the Earth, the moon, or Mars and return to the Enterprise. More broadly, the idea of the Universal Lander is to create a super-robust spacecraft that can fly and land anywhere in our solar system that is hospitable to human visitors.
The Universal Lander is a SSTO (Single Stage to Orbit) type spacecraft. This means that it can launch from the Earth, the moon, or Mars with only the rockets and fuel within the craft. Thus there are no add-on external fuel tanks or boosters that are jettisoned during a launch of the Universal Lander like has long been a familiar sight when watching launches of spacecrafts carrying humans. An example of an SSTO was the X-33 spacecraft (shown in the image) that was canceled by NASA in 2003 just before flight testing was to begin. There are also many other SSTO crafts being investigated today (like the Skylon), although funding is very low.
When on Earth, the Universal Lander works like an airplane. You fuel it up, and it flies to its destination. After getting there it only needs to be re-fueled before makings its next trip.
SSTO spacecraft are used to improve reliability, reduce maintenance, increase safety, and reduce costs. All of these are good reasons to pursue a SSTO type craft when developing the Universal Lander.
Designing the Universal Lander so that it can land on or launch from Earth, the moon, or Mars presents unique engineering challenges. For one, the Earth has an atmosphere while the moon does not. And Mars has a very thin atmosphere compared to Earth. Thus the flight characteristics of the Universal Lander will be very different when flying in each place. Providing versatility in flight must be a driving principle during the development of the Universal Lander.
In the spirit of versatility, the Universal Lander can land in three different ways:
- Glide unpowered to land on an airstrip like the space shuttle when on Earth.
- A powered landing on to an airstrip like an airplane when on Earth or on Mars.
- Thrusters deploy to enable a vertical landing whether on the Earth, the moon, or Mars.
The Universal Lander can take off two different ways:
- Horizontal takeoff using a runway like an airplane when on Earth or on Mars.
- Vertical takeoff by using vertical thrusters and then engaging the horizontal engines to make an angled ascent upwards whether on the Earth, the moon, or Mars. (This is similar to a Harrier jet takeoff.)
The Universal Lander can fly around like a plane whether on Earth, the moon, or Mars. When on Earth, it can fly very efficiently in terms of fuel usage because there is a thick atmosphere to provide lift to its wings. It can take off and land at commercial airports. On Mars it can get some lift from its wings too, but not a lot. Thus on Mars the wings are used, but also the vertical thrusters may often need to be engaged even during horizontal flight. On the moon, the wings are immaterial since there is no air that strikes them to create lift. In this case the craft is moved solely by the vertical thrusters and horizontal engines.
Because the Universal Lander can take off and land horizontally, it is referred to as a HTOL (Horizontal Take-Off and Landing) spacecraft. Thus the Universal Lander is both a SSTO and HTOL spacecraft.
But, because the Universal Lander can optionally take off and land vertically, it is also a VTOL (Vertical Take-Off and Landing) spacecraft.
The Universal Lander is therefore a SSTO, a HTOL, and a VTOL all in one; it can launch, fly, and land in numerous orientations. It can fly at very high speed when needed, such as when leaving Earth to go into orbit. But it can also fly at very slow speeds when needed. Thus the Universal Lander is the ultimate flexible flying machine whether near the surface of Earth, moon, or Mars or when out in space.
The Universal Lander is limited in its range due to its fuel tank capacity. However, if refueled along the way, the Universal Lander could fly all the way from Earth to the moon – land on the moon – and then fly back and land on Earth. This may not be a practical mission, but the Universal Lander has this capability.
The Universal Lander can also fly into the upper atmosphere of Venus. It can descend down to about 30 miles above the surface. It cannot go lower than this because the temperature on the surface of Venus is 1000 degrees F. Designing the Universal Lander to withstand 1000deg F is likely too difficult of a goal for the first generation of the Universal Lander. It will be plenty challenging enough achieving the Universal Lander’s distinctively versatile flight capabilities.
Finally, an SSTO, to be possible, must have a very high mass ratio (ratio of the propellant mass to the ship’s structural mass). This means that the ship’s structure and contents must be very lightweight. The mass ratio needs to be between about 10 to 25 (i.e. 24 parts propellant mass to 1 part structural mass).To support this requirement, the Universal Lander will carry, besides humans, very little payload. A payload carrying capacity of just 10,000 pounds or so should be adequate. Any large cargoes, such as base-building equipment that must be sent down to a planet or moon, will be sent down using robotic landers instead of using the human-carrying Universal Landers.