1.1.   Mission Objectives

The first NMSUSat mission was designed so that specific attitude control capabilities were not required [8].  Since this was the first satellite to be designed and constructed by the students and faculty at NMSU, this simplifications was deemed an acceptable design compromise.  However, to enable science and engineering missions to be formulated that are more ambitious than those possible with no attitude control, the ability to design a satellite with a minimum of two-axis control is considered to be a key next step in the evolution of designs for NMSU.  The mission objectives for the NMSUSat2 program will cover three areas in technology and educational development as part of the university’s long-range road map.  The NMSUSat2 mission objectives are as follows:

1.      To develop the means for passive, two-axis control of the satellite to provide the basis for achieving
      subsequent science and technology mission objectives.

2.      To use the stabilized platform to demonstrate basic robotic capabilities to gain experience for
      conducting future robotics and on-orbit servicing missions.

3.      To continue the educational enhancement in aerospace-related topics for support components as part of the development
      of the aerospace engineering program within the College of Engineering and to develop multi-disciplinary capstone and
      design classes for students in engineering departments and the engineering physics program.

 1.1.   Mission Success Critieria

1.      The goals for the technology development testbed are
      – To use the robotic arms for estimating the inertial properties of the satellite
      – To demonstrate the use of a high speed modem with a channel data rate of at least 56 kbps
      – To demonstrate the use of VDHL technology to encapsulate flight computer system on a single chip.

2.      The goal of educational enhancement is to have at least 50 students involved with the project as part of their design education requirements.

 1.2.   Experiments

The technology experiment for the NMSUSat2 mission is the demonstration of control of the platform via passive means.  Once this control is achieved, the satellite will conduct robotic motions using a dual-arm robot attached to the satellite.  The robotic arms will image the satellite and earth.  The imaging will be used to validate the control of the platform and control of the arms.  If control is achieved, then better pointing of the satellite will result and a higher communications data rate than the current 9600 bps will be used to transfer images and satellite health and welfare data.  Improved communications will permit more ambitious science and engineering missions in the future.

 1.3.   Justification

The NMSUSat2 mission objectives will meet the following University Nanosatellite programmatic needs:

1.      The Air Force and NASA have identified the general area of robotics and on- orbit servicing as a relevant technology application for the University Nanosatellite Program. The NMSUSat2 mission will have this topic area as its primary mission focus. It is expected that mission success on this satellite will enable NMSU to pursue more advanced concepts along this line.

2.      The University Nanosatellite Program is interested in developing sensors and actuators for guidance, navigation, and control. The measurement of the inertial properties and the stabilization technology for the NMSUSat2 mission is expected to be relevant to these needs.

3.      On 3 Corner Satellite and the NMSUSat programs, NMSU developed standardized radio communications technologies. The basic NMSU design was used by several of the schools in the University Nanosatellite 3 Program. In particular, the University of Colorado and NMSU are using the NMSU modifications to the 3 Corner Satellite radio system to achieve higher data rates (9600 bps vs. 1200 bps). With a stabilized platform, the NMSUSat2 mission will be able to achieve higher data rates for space- to- ground communications. The radio design for this will be shared with the wider University Nanosatellite Community with the goal of making the design useful to other schools.

4.      NMSU will continue with designing in standard data communications technologies to illustrate IP- based communications standards as part of the intrinsic satellite design.

 1.4.   Spacecraft Design

A nanosatellite will be designed to provide the operational support to carry out the technology and educational mission elements.  This satellite will be designed to fit the nominal design envelope of a mass not exceed 30 kg and linear dimensions not to exceed 45 cm at the widest point.  The design will be carried out to the Engineering Design Unit (EDU) level.  A preliminary concept design for the nanosatellite is given in Figure 1. The final design of the system (such as the configurations of the booms and arms) may look different than what shown in the figure.  The major satellite subsystems are summarized in the following paragraphs.