With the given constraints of the space environment, the telescience concept aims at providing a space mission user with optimum flexibility and responsiveness for spaceborne investigations. The concept includes automated system management functions, which allocate and monitor planned resources and time windows, within which the investigator can perform his science interactively responding 'on-line' to experimental data. During the telescience operation, the user is given the capability to send telecommands to the payload from the User Home Base with transparency to the rest of the system. Any violation of the 'booked' time and resources will be detected by the system and reported back to the user for appropriate action. Ultimately, the system will react to maintain the integrity of the system and its payload. Upon completion of the telescience session, the system management function reverses the system configuration and deallocates resources automatically

Lytton, David W.

Schulze, Rolf

English

NASA Technical Reports Server

.12 
Postbus 299,2200 AG, Noordwijk, Netherlands 
CT 
With the given constraints of the space environment, 
the telescience concept aims at providing a space 
mission user with optimum flexibility and 
responsiveness for space-borne investigations. The 
concept includes automated system management 
functions, which allocate and monitor planned 
resources and time windows, within which the 
investigator can perform his science interactively 
responding "on-line" to experimental data. During 
the telescience operation, the user is given the 
capability to send telecommands to the payload from 
the User Home Base with transparency to the rest of 
the system. Any violation of the ''booked" time and 
resources will be detected by the system, and 
reported back to the user for appropriate action. 
ultimately, the system will react to maintain the 
integrity of the system and its payload. Upon 
completion of the telescience session, the system 
management function reverses the system 
configuration and deallocates resources 
automatically. 
Keywords: 
COL W U S ,  APM, Telescience, Principal 
Investigator, Payload Operations 
1. ODUCTION 
The ESA COLUMBUS Attached Pressurised Module 
(APM), the European contribution to the Space 
Station Freedom, provides for an inhabitable 
laboratory environment and is conceived to be 
operated automatically, from the ground, and by the 
on-board crew. 
The operation of on-board payloads can be done: 
C. either through pre-programmed automatic 
operations, invoked by the Space Station master 
timeline (Onboard Short Term Plan - OSTP), 
and processed accordingly by the APM element 
manager, 
or through telescience operations, defined as 
"the fully interactive mode of science operations 
whereby investigations on the Space Station and 
COLUMBUS elements are carried out under the 
effective scientific control of the investigator 
teams" {ref-l}. This involves payload user 
operations via telmmmands, issuing payload 
internal comunands, with complete transparency 
of the rest of the APM system. 
Both types of operation are supervised by automatic 
management functions to set and monitor operations 
envelopes, within which scientists can undertake 
their scientific investigations. Telescience is used for 
shorter duration payload activities such as swapping 
samples in an automated material processing 
furnace, whereas payload operations via the OSTP 
are used for long duration payloads and are 
characterised by Principal Investigator monitoring. 
This paper outlines the COLUMBUS approach 
towards telescience operations, and the operational 
procedures, functions and communication seMces 
required to support the concept. 
2. COLUMBUS APM OVERVIEW 
Following complete attachment to the SSF node, 
activation and checkout, the APM will be ready to 
support payload activities as required by the SSF 
mission operations schedule. The payload activity 
support provided by the APM will include the 
operation of payldaas from the International Partners 
(NASA, ESA, and CSA). The APM system will be 
under the control of the APM System and Mission 
Management ( S W  Software, which will respond 
to messages and commands sent from the SSF 
Integrated System Executive (ISE), the crew and 
ground. APM on-orbit servicing and maintenance 
will be planned and provide for the full 30 year 
operational life. It will be seMced and maintained 
during 90 day (tbc) increments, enabling the 
resupply of c o d l e s ,  the changing of 
International Standard Payload Racks (ISPRs) or of 
individd payload subunits within the rack, and 
hence suppoxting a diverse range of scientific 
operations in the Me sciences, space biomedicine 
and material sciences. 
3.1 AeM Automatic Command Execution 
In order to increase operational flexibility, auto 
system level management functions are provi- 
https://ntrs.nasa.gov/search.jsp?R=19940019404 2020-06-16T15:38:02+00:00Z
(system level Failure 
Detection, Isolation Bt Recovery - FDIR); 
reporting APM system data to the ISE. 0 
This enables the APM to be operated as a ground- 
based laborato~~ without the continuous 
commanding and monitoring that has characterised 
previous spacecraft missions. This reduces the 
impact of limitations of up/downlink capabilities, 
and loss of signal @.OS). 
Pre-planned automatic on-board operations within 
the APM are nominally invoked by the OSTP, 
running within the Space Station Manned Base 
(SSMB). Commands that are applicable to the APM 
are sent to and processed by the SMM, and may 
comprise time-tagged Action-Names or Operational 
Task-Names. An Action is the lowest operational 
step by which the APM can be controlled and 
operated within the context of nominal operations. It 
is associated with a step change in resou~ce 
allocatioddeallocation, and a functional process to 
be performed utilising this resource. An Operational 
Task (0") groups together Actions related to the 
same mission goal. 
3.2 APM Resource Management 
The resource management function of the SMM 
handles all aspects of on-board resource 
management, including: 
0 resource allocation checks; 
0 resouTce allocation data management; 
0 resou~ce consumption monitoring; 
0 resource reporting and logging to SSMB/crew/ 
ground. 
For the APM, the following principal resources are 
provided and managed: 
0 powerdistribution; 
0 data management seMces; 
0 cooling (air and water); 
0 vacuum line allocation; 
0 venting line allocation; 
0 nitrogen (purge gas) distribution to payloads. 
the individual users, and may be 
User Home Base (UHB) or at the collective User 
Support and operations Centres (VSOC) level. This 
is shown in figure 1. The sum of all the individual 
resource envelope allocations (e.g. USOC-a plus 
USOC-b) makes up the envelope for utilisation (i.e. 
the total amount of resources allocated to APM 
-1. 
Against these resources are set "sofin (operational) 
limits which are the limitations imposed upon the 
user of the particular resource, and "hard" (design) 
limits which represent the fixed thresholds of the 
resource, the exceeding of which may result in 
damage to the consumer. 
4.0 TELESCJENCE OPERATIONS 
4.1 Teiescience Concept 
The fundamental idea of telescience is to exploit the 
advances in both comunidons, and information 
technology to enhance the scientific return from 
space-based activities; the former are related to the 
exchange of information, the latter related to on- 
board data processing such as data reduction and 
ground-based user workstation software support, 
This forms the basis for a wide range of telescience 
applications, ewling the principal Investigator PI) 
to conduct scientific investigations in a decentralised 
manner (i.e. not in the SSCC or Payload Operations 
& Integration Centre - POIC) from a facility 
applicable to his particular scientific discipline, as 
shown in Figure 2. This may invoke the seMces of: 
0 quasi real-timeheat real-time operations; 
0 teleoperations; 
0 telemanipdation (robotics); 
0 ground-expertsystedAI. 
The expected net benefits of this would include an 
optimisation of the utilisation of crew time, and an 
increase in the efficiency of the results obtained 
(both qualitative and quantitative) through the direct 
involvement of the PI in on-board payload 
operations. 
2% 
Payload : 
Payload 2 
Payload 3 
F p r e  I Resource Envelopes 
A general telescience scheme, in which there is a transparency to the rest of the ground infrastructure, 
mission operations control centre responsible for the comprising the mission control centre for the system 
monitoring and control of the flight system, and a set and payloads, and the ground stations providing the 
of PIS at their home bases is shown in figure 2. The up/downlii. The expected duration of a telescience 
users would receive the scientific data applicable to session is in the order of 15 minutes to 8 hams {ref. 
their particular experiment, whilst having the l}, dependent upon the scientific discipline under 
capability to directly send telescience commands to investigation. 
their experiments. This is performed with complete 
Ground Station t 
I Mission Control Centre I 
Command Requests 
PqbadData 
Figure 2 Basic Telescience Concept 
287 
.2.1 rence co 
resuit in the set-up of a 'telescience mode' for the 
payload concerned, and its associated reference 
configuration. Attached io this will be the resource 
allocations for its particular operational period or 
window. This forms the bun- or envelope for the 
payload to operate within. The telescience period 
may run in parallel with the automatic operation of 
other payloads, defined within the OSTP. At the 
beginning of the operational window, as directed by 
the Actions and OTs, there will be an automatic 
configuration of the APM to support the payload 
operation, and the PI will be informed, &en the 
system is configured for commencing telescience 
operations. The telescience operations themselves 
however, are left with the user. At the end of the 
operational period, the payload will be configured by 
telescience commands or the OSTP to a 
configurational status such that it is left in a stable 
state, and the APM system will be configured by the 
OSTP according to the next set of pre-planned 
operations. 
4.2.2 Command authorised system resources for 
payload execution 
As with the automatic operations mode, the APM 
system will be responsible for commanding those 
core system resources required to support payload 
execution (e.g. power, DMS seMces). The resources 
agreed by the ground will form operational and 
design envelopes which cannot be transgressed, but 
within which the PI will be able to operate, utilising 
those resource envelop in real time. Transgression 
of these limits, including "booked time" would result 
in a waning being issued by the system requesting 
correction back to within the agreed margins. 
Failure to perform this would result in the system 
reacting to maintain the integrity of the system and 
the other payloads. The system will also initiate 
predefined responses if a system resource cannot be 
provided. 
For telescience operations, resource management 
will be performed in two ways: 
o pro-active checking, performed before 
execution; 
o reactive checking performed on-board, but also 
on the ground (@ POIWSOC) in real-time. 
It is obviously desirable to eliminate as much 
redundant checking as possible, since this will 
inelude: 
in  on ofon/o€€commands; 
- furnacetemperahue, 
- timedurations, 
- mtationangles; 
setting of on-board payload software control 
0 setting ofvariable experiment parameters 
0 
0 payload reprogramming; 
0 continuous control (e.g syringe control). 
Commands and messages will be routed directly to 
the payload, without any intervention or checking by 
the SMM, which simply monitors resource 
consumption. Telescience commands comprise of 
'real data' which are unintelligible to the system. 
They may form parametric values which are 
interpreted directly by the payload or by a payload- 
provided command sequencer. In the case of the 
latter, theses sequences may issue internal 
commands held on-board, with interactive control by 
the PI (e.g. insertion of parametric values to the 
stored payload commands). 
4.2.4 Optimised Onboard Data Routing 
For telescience operations, optimised data routing 
with a minimw end-toend communications delay 
is a pre-requisite for both uplink as well as downlink. 
From the user community's point of view, a forward 
link time delay of 2 seconds maximum and a return 
delay of 1 second maximum are preferable. At 
present, this is not supported, with a total end-toend 
loop delay in the order of 10 seconds {ref 2). 
Ground links are considered in section 5. 
The current onboard forward link response is 
dependent upon two factors: 
o 
e 
the performance of the onboard routers and 
associated protocols; 
the number of database accesses which any of 
the command processing elements will have to 
make (SSMJ3 RunTime Object Database - 
RODB, SMM Onboard Database - OBDB), and 
the corresponding LAN loads. 
An outline of the onboard routing (according to the 
architecture presented at COLUMBUS System 
Requirements Review (SRR) in July 1992), is shown 
in Figure 3: 
288 
i 
t bnpass0fSMM 
_i directroutingtop/ls 
reception of PL command packet at ISE node 
identification of APM specific packet 
forward passing to gateway 
1\ direct commanding from ground 
Fgure 3 Telescience Command Routing 
4.2.5 Overall Telescience Operations Concept 
A general schema for the operation of the payload is 
shown in figure 4. 
F Z e  4 Tekcience On-Board Operations Concept 
289 
and use of its particul 
nt, whilst the USOC is responsible for the 
payload facility in which the instrument may be 
contained. The MSCC (rbc) coordinates all 
European users of the SSF, and hence has to ensure 
that the resource budget that is allocated to the APM 
is adhered to, and coofdinates the UHBs/LTSOCs 
accordingly. 
5.2 User Home Bases (UHBs) 
The UHB will have the following responsibilities: 
0 for a single experiment; 
0 execution of experiment; 
0 evaluation of scientific results; 
0 off-line planning interaction. 
5.3 User Support and Operations Centres 
W S ~ S )  
A particular USOC will have the following 
functions: 
e responsible for an onboard facility, containing a 
set of payload subunits; 
e facility operations (including all system 
resources); 
e facility checkout; 
0 facilitysupport. 
5.4 Operations Scenario 
Interactive payload operations are based upon the 
ability of the user within the UHBAJSOC to utilise 
an authorised set of commands which are routed 
through the POIC/CCC in the USA for 
authentication and authorization. The command set 
would be accessed via a user Work Station (UWS), 
allowing the control of the payload. These 
commands would have been validated off-line within 
an integrated simulation of the APM and would be 
checked on-line only for their sourddestination 
authority. 
Return data, comprising of payload housekeeping 
data and scientific data (up to 30.85 Mbps) is routed 
from the ground station directly to the USOC/UHB 
concerned. 
for merent users in terms of access to telescience 
operations, quality of seMce, and data capacity. 
ACRONYMS 
AI 
APM 
ccc 
C&T 
CSA 
DMS 
ESA 
FDIR 
ISE 
ISPR 
LAN 
LOS 
MMC 
MSCC 
OBDB 
ODF 
OSTP 
OT 
PI 
PL 
POIC 
RODB 
S M M  
SRR 
sscc 
SSF 
SSMB 
UWB 
usoc 
1. 
2. 
Artificial Intelligence 
Attached Pressurised M d d e  
Control Centre Complex 
Comms t Tracking Subsystem 
Canadian Space Agency 
Data Management Subsystem 
European Space Agency 
Failure Detection, Isolation t Recovery 
Integrated Station Executive 
International Standard Payload Rack 
Local Area Network 
Loss of Signal 
Mission Management Computer 
Manned Space Laboratories Control Centre 
Onboard Database 
Operations Data File 
On-Board Short Term Plan 
Operational Task 
principal Investigator 
Payload 
Payload Operations t Integration Centre 
Run Time Object Data Base 
System and Mission hhagement 
System Requirements Review 
Space Station Control Centre 
Space Station Freedom 
Space Station Manned Base 
User Home Base 
User Support and Operations Centre 
REFERENCES 
Telescience Working Group Results, May 
Columbus Users End-&End Telematic 
Network (C0UElT.E) Final Report, July 
1991 
14-15, 1991 
290 


Columbus system support for telescience operations

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server