Dec 20, 2011

Breaking, Descent and Landing

Now here is where the fun really begins, it's not every day you land a robot on the moon! The Breaking Stage solid motor is used to reduce the spacecraft's speed on its approach. The direct descent landing trajectory chosen means the Lander can touch down just after lunar dawn allowing the maximum amount of time to complete the mission but also requires the timing of this burn to be very precise. To achieve this precision an on-board timer is used to trigger the ignition when the Lander passes through a specific lunar altitude. After the Lander separates from the Breaking Stage it follows a gravity turn trajectory (illustrated in the image) to the surface using its own rocket engine to control its descent. During the final approach to touchdown the Lander determines its altitude and vertical velocity using a small radar altimeter and its horizontal velocity by a landing camera coupled with the altimeter and rate gyros. Finally, after travelling a quarter of a million miles, the Lander touches down on the moon's surface and prepares to deploy the Rover and complete the GLXP mission.

Dec 14, 2011

Simon O'Reilly

Simon O'Reilly is the PR Manager for White Label Space and in that role he also looks after the team's social media presence.

Simon has a keen interest in astronautics, theoretical physics and astronomy and has read extensively on these subjects.

He received a First Class Honours Degree from Trinity College Dublin in Mechanical and Manufacturing Engineering where he studied various modern manufacturing techniques and processes as well as their organization and management. His final year thesis was on "The Effects of Microjets on Jet Turbulence".

Simon's contact details are:


Guidance and Navigation Control

Throughout the mission it is vital that the position and orientation of the spacecraft are precisely known so that it can be guided to the chosen landing site on the moon. Standard ground tracking techniques are used to accomplish this.
Soon after the Trans Lunar Injection burn and stage separation, a first Mid-Course Manoeuvre (MCM) is performed using the Braking Stage Reaction Control System. A sufficiently large delta-V for the MCM is provided for this burn that serves to compensate for injection inaccuracies of the solid motor. One or more subsequent MCM manoeuvres are performed throughout the rest of the lunar transit to accurately target the landing site. Following this the breaking stage is used to slow the spacecraft to a safe velocity for landing on the moon.

Dec 8, 2011

Attitude Control

The orientation or attitude of the spacecraft is critical at all stages of the mission. After the Trans Lunar Injection stage is complete the spacecraft stack begins its three day long journey to the moon. The difference in temperature between the side exposed to the sun and the side in the shade can be as high as 135 degrees. This temperature gradient can cause structural damage to the spacecraft and effect the performance of the Breaking Stage solid motor. To ensure that the temperature is distributed evenly a monopropellant Reaction Control System (RCS) is used to slowly spin the spacecraft about the flight axis.
The RCS is also used to perform any Mid-Course Manoeuvres (MCMs) needed during the lunar transit and to optimise the spacecraft's attitude for the breaking burn on approach to the lunar surface.

Dec 5, 2011

Lander Drop Test 1

The White Label Space engineering team conducted a first proof-of-concept test of a new concept for impact absorbing legs. Making best use of available hardware, the team integrated the new trial leg assembly on the existing mock-up of the lander. A sensor system was used to measure accelerations during the drop.

Trans Lunar Injection (TLI) Stage

The Polar Satellite Launch Vehicle can be used to launch the spacecraft stack into Geostationary Transfer Orbit (GTO) but then a second rocket impulse is needed to transfer from this orbit into the Lunar Transfer Orbit (LTO) required to complete the mission.
This part of the mission is referred to as the Trans Lunar Injection (TLI) stage and is accomplished using a Star30BP solid motor. The spacecraft is first stabilised by spinning it about its flight axis using a small motor which thrusts in the tangential direction before the Star30BP fires to inject the stack into LTO. A yo-yo de-spin mechanism is used to slow the craft's rotation after the TLI stage is complete, a video demonstrating a yo-yo de-spin can be viewed here. If either the Soyuz Fregat or Falcon 9 launch vehicle is used then the spacecraft stack is placed directly in LTO so the separate TLI stage rocket is not needed.

Dec 2, 2011

The Launch Vehicle

Every space mission begins with a rocket launch and the mission planned by White Label Space is no different. The launch will place the spacecraft in a parking orbit above the earth before it is propelled further to LTO (Lunar Transfer Orbit). From here the spacecraft follows an orbit which brings it increasingly under the effect of the moon’s gravity until, after a three day journey, it reaches the moon.
The launch will be carried out using one of three low-cost launch vehicles with which the spacecraft stack designed by White Label Space is compatible; the Polar Satellite Launch Vehicle (PSLV-XL) developed in India, Russia’s Soyuz Fregat or SpaceX’s Falcon 9.

The larger size of the Soyuz Fregat and Falcon-9 launchers allows for additional payload capacity. These launch vehicles could carry one or more other passenger spacecraft to LTO, potentially including other GLXP competitors. This would considerably reduce the launch costs incurred by each organisation and so offers a clear financial advantage to any private or government funded missions.
While the Soyuz and Falcon launch vehicles can deliver a payload directly to LTO the PSLV-XL does not have this capability and so an additional rocket would be needed to perform what is known as a TLI procedure (Trans Lunar Injection). Once the TLI stage rocket has inserted the stack into LTO, it separates and is discarded, leaving the three remaining components of the spacecraft stack; the braking stage, Lander and Rover, to continue on their course to the lunar surface.