Supporting Space/Ground Communication During Asynchronous Conditions

The communication protocol we created is a structured template. Its content not only addresses the problems with asynchronous communication that we identified in our research, but also incorporates recommendations put forth by Love and Reagan (2013). Its structural characteristics are informed by schema-based approaches to instruction design (Morrow & Rogers, 2008; Morrow, Leirer, Andrassy, Decker Tanke, & Stine-Morrow, 1996; Morrow, Leirer, Andrassy, Hier, & Menard, 1998; Morrow et al., 2005) (Figures 6.2 and 6.3).

We developed two protocol versions - one for voice-only communication, and one for text-based communication - to account for medium-specific affordances and constraints. As shown in Figures 6.2 and 6.3, a protocol consists of four segments and several communication conventions that tackle the major challenges of asynchronous communication - Time, Conversational Thread, and Transmission

Protocol template for voice communication

FIGURE 6.2 Protocol template for voice communication.

Protocol template for text communication

FIGURE 6.3 Protocol template for text communication.

Efficiency. Medium-specific instructions concern aspects of the call sign and conventions that follow from characteristics (or limitations) of audio or text communication. The call sign during voice communication for instance needs to do more than identify who is talking to whom. It also needs to catch remote partners’ attention because they may be engaged in some other task and the communication may come as a surprise. Thus to ensure attention capture, an addressee’s name should be called out twice, as in the following example from HERA: MCC, MCC, Graphos. Time is 11:03. The call sign, moreover, needs to anchor a message in time to highlight the temporal sequence of participants’ contributions and thus safeguard against proximity bias. All references to time need to be independent of a partner’s perspective and should be linked to an objective time, such as standard time. As text messages typically include time stamps and the identity of the sender, call signs need to identify only the addressee. On the other hand, because the texting tool may not have an attention-getting feature such as announcing incoming messages with a chime, protocol conventions direct partners communicating via text to note the time of both their transmission and the expected response and to check for new messages accordingly. Text communication provides a written record of partners’ contributions; thus no record keeping is required. In contrast, when distributed team members communicate by voice, protocols require them to maintain a log of their ongoing discourse to keep track of conversational threads.

Medium-independent instructions concern the topic section of a message, the message body and the final - closing - section as well as several conventions designed to support conversational coherence, message comprehension and shared task understanding, as well as communication efficiency. To this end, team members should preface their messages with a topic, or make explicit the relationship of their message to a preceding one from their partner (e.g., response to a specific question, information requested, etc.). This behavior is evident in the message by the HERA crewmember quoted above as it continues with: This is CDR with a System Update. I have three numbers. They are: 106, 107 122. Again the numbers are 106, 107, and 122 Over. Likewise, MCC explicitly links her response to the commander’s message: Graphos, Graphos, MCC for Commander. System Update received. 1 have the following numbers: 106, 107, and 122. Providing and referencing a topic enables partners to keep track of conversational threads and avoid proximity bias. Team members are also instructed to transmit all relevant information in one turn, to present it in a clearly structured fashion, to repeat critical items, and to postpone transmission of non-time- critical information while they await crucial input from their partner. These elements are meant to facilitate comprehension and maintain communication efficiency as related information is kept together. Mutual understanding is further enhanced when team members explicitly acknowledge and paraphrase or “readback” a partner’s messages instead of providing generic feedback, such as “copy all.” Moreover, by indicating their understanding of a partner’s message, team members can preclude unnecessary communication. Appropriate feedback is essential; if no feedback is given, partners may repeat their message or ask for verification. Likewise, team members are told to note when they should receive a response to discourage unwarranted repetition that could potentially confuse their partner. Lastly, team members are instructed to announce when they plan to transmit important information to cue their remote partner to attend to it, and to mark the end of a transmission to let partners know that their message is complete.

The communication protocol was implemented in several space-analog simulations to assess their usability for space exploration missions. One set of studies was conducted at NASA’s NEEMO facility, an undersea research station 62 ft below sea level off Key Largo. In NEEMO, as Herve Stevenin, a crewmember of mission 19, recounts

we simulate a mission to Mars and its moons. Not the way to fly to it, but our simulation started around Mars. Here we are, with 5 minutes delay in all our communications with Mission Control. If we have a question, we can only get the answer at the earliest 10 minutes later. It requires to be clear and concise in our communications and we test different operational modes and tools to assess the best set-up for such a mission to Mars. Aquarius is our “spaceship”. We all feel, that we are part of it. (Stevenin, 2014)

Crewmembers of two missions, NEEMO-18 and NEEMO-19, agreed to use the medium-appropriate communication protocol during space-ground interactions on days with a communication delay. Each mission involved four crewmembers from the astronaut corps of NASA and its international partners (CSA; ESA; JAXA).

The second set of simulations took place in NASA’s Human Exploration Research Analog (HERA), a space-analog habitat located at Johnson Space Center. Four missions were dedicated to the study of the impact of space stressors (confinement, isolation, communication delay) and of countermeasures on crewmembers’ physiological and psychological well-being. Each mission included four crewmembers who were astronaut-like research volunteers; that is, individuals comparable to astronauts in terms of education, physical fitness, personality, and age.

Crew and mission control personnel of the NEEMO missions and of the last two of the HERA simulations received 30 minutes of communication training during the pre-mission phase. Communication training identified the challenges of asynchronous communication and explained the elements of the communication protocols and conventions. There was one joint training session for participants in the NEEMO missions, 5 weeks prior to NEEMO-18 and 13 weeks prior to NEEMO-19. The NEEMO-19 participants received a refresher training 3 weeks before their mission started. HERA crewmembers and HabComs (i.e., personnel of the Flight Analogs group at JSC acting as HERA mission control) of missions 3 and 4 received training during the week preceding their mission; participants of missions 1 and 2 served as control and thus did not participate in any communication training.

NEEMO-18 was a 9-day mission with 4 days of communication delay. Two days involved a delay of 5 minutes one way, the other 2 days presented a 10-minute delay. Communication medium (voice vs. text) was crossed with communication delay. NEEMO-19 lasted for 7 days. On 4 days, communication between the crew and mission control was delayed by 5 minutes one way, and remote partners could choose which medium (voice or text) to use during a given interaction.

HERA missions were 7 days long and included 2 days during which communication was delayed by 10 minutes one way. On the first of these days, communication between the crew and mission control was voice-only; on the second day participants were given a choice of communication medium (voice or text).

In all NEEMO and HERA missions communication delay occurred on consecutive mission days. Copies of the communication protocols were given to trained participants at the start of a mission to serve as a reference aid on days with a transmission delay.

A daily survey administered to NEEMO-18 crewmembers included one question that asked participants to rate the effectiveness of their communications with mission control. In addition, a separate survey was given on the days on which communication with mission control was delayed. In this survey crewmembers were asked to evaluate the extent to which the communication protocol and conventions were effective in supporting communication with mission control during important events of the day. On the mission day immediately following the days with communication delay, crewmembers received a survey in which they were asked to rate how critical each of the elements of the protocol and individual conventions was in facilitating asynchronous communication. In NEEMO-19 only the communication-specific and final surveys were included due to mission constraints.

HERA crewmembers were given daily communication surveys assessing the effectiveness of their interactions with mission control during assigned tasks. HERA crewmembers who had communication training also completed a final survey at the end of their mission evaluating protocol elements and communication conventions.

Given the small sample size, only descriptive statistics were conducted on participants’ ratings. This analysis is summarized in Table 6.1 and indicates that trained participants considered the protocol to be effective in supporting crew/MCC communication when there was a transmission delay. Astronauts in the NEEMO missions as well as trained volunteers in the HERA simulations gave effectiveness ratings >4 (out of 5). Moreover, participants’ ratings of crew/MCC communication suggest that the protocol “normalized” interactions on days with communication delay. As can be gleaned from Table 6.1, trained crewmembers perceived that the effectiveness of their interactions witli mission control did not suffer when communication was delayed. In contrast, untrained HERA crewmembers gave considerably lower effectiveness ratings on time-delay days compared to days with synchronous communication. Untrained HERA participants also commented that they were less willing to contact mission control for guidance on tasks when their communication


Crewmembers' Mean Effectiveness Ratings of Their Communications with Mission Control (MCC)

Effectiveness of Crew/MCC Communication

Effectiveness of Protocols

No Comm Delay

Comm Delay


4.46 (0.69)

4.31 (0.48)

4.69 (0.52)





HERA (trained crews)

3.93 (0.89)


4.25 (0.46)

HERA (untrained crews)




Notes: Numbers reflect mean ratings across days (days with communication delay vs. no delay); standard deviations are in parentheses. Maximum rating was 5.

was delayed. As a result, as mission control noted, they performed the tasks improperly and required time-consuming additional assistance from ground.

Crewmembers generally rated protocol elements and conventions as fairly critical to ensuring effective communication with MCC during asynchronous conditions, and tended to follow the protocol as the exchange between the NEEMO-18 crew and MCC shown below illustrates (Fischer & Mosier, 2016). However, this example also indicates that some protocol elements were not consistently applied. Both crews and MCC failed to repeat the initial call sign or dropped the closing in some of their voice messages. While a falling intonation may suffice to signal the end of a message, there is no comparable way to signal a message beginning and its target. Failure of MCC to state the initial call sign twice in MCC-1 may have contributed to the crew’s partial understanding of that message as expressed in their third call to MCC. The exchange also highlights the importance of message timing - to specify for partners and take into account for oneself the time a message was transmitted. As can be seen, both the crew and MCC transmitted messages at 8:04. The message from MCC (MCC-3) was an answer to the crew’s initial request (Crew-2), but it also, fortuitously, addressed their second (repeat) request in Crew-3. MCC, on the other, faced a more confusing turn sequence. Five minutes after they had transmitted the heading information to the crew, they received the crew’s request to repeat this information. MCC apparently did not take into account the time of the crew’s latest message; if they had, they would have realized that the crew by now would have received the required heading information and that no additional response was necessary. Instead, MCC repeated their instructions; however, this time they tied their feedback explicitly to the crew’s preceding messages and thus established that the heading information was now knowledge shared by crew and MCC.

Crew-1: MCC, Aquarius on space-to-ground 2, we have some question for you regarding the EPR. We will transmit in a minute. Then it wall be 7:50 am. Crew-2: MCC, MCC this is Aquarius on space to ground 2 regards the EPR. We do not have the headings for the EVA activities. We have some maps and the distance but we do not have the bearings for each site. If you can inform us about the headings for each site before the EVA starts we would appreciate it. And that’s it from Aquarius. Have a great day.

MCC-1: Aquarius, MCC. We just received your message concerning the bearings for the EVA. We will work on that, and we think we will provide you a file with the updated distances and bearings and ahm in a little bit. We will let you know as soon as we send them.

Crew-3: MCC, MCC, Aquarius. It is 8:04 am. And we heard a call regarding the heading for the mission today. The crew' has a distance but they do not have a heading. So please repeat the heading for the crew'. Again. MCC, MCC, this is Aquarius. End of transmission.

MCC-2: Aquarius. Aquarius, MCC at 8:04 on the <> loop. We do have a new picture showing the distances and heading, and we send them up to you via the mission log. Repeat. We have a picture with distance and heading for the EVA, and we're sending it up on the mission log. Out.

MCC-3: Aquarius, Aquarius, MCC on 2 for EVA message. We will give you 15 seconds and then we go with the message.

MCC-4: Aquarius, Aquarius, MCC for the EVA. We heard your messages requesting headings for the EVA. We have now posted a file, a picture on the mission log with the distances and headings, approximate headings. They are not absolutely precise, approximate headings. That should answer your questions.

Table 6.2 presents NEEMO and HERA crewmembers’ criticality ratings of protocol elements and communication conventions. As can be seen, the majority of the items received a criticality rating of at least 3.5. Very high ratings across crews for several items - providing a topic, using a log to track related messages, and announcing complex or critical messages - reflect the value of protocols for keeping track of message threads. However, ratings by NEEMO crewmembers for some items - most notably, pushing and chunking information and tracking time - were surprisingly low. This finding may indicate that crewmembers underappreciated the importance of these elements and point to specific training needs and technological improvements.

The importance of technological improvements to facilitate communication is apparent in NEEMO 19. During this mission the crew opted to use exclusively text as their communication medium on time-delayed days. Their choice may reflect the implementation in this mission of a new' text tool (VOXER) whose features seem better suited to meet the demands of asynchronous communication than the text tool that was available in NEEMO-18 and HERA. For instance, with VOXER the time a message w'as sent was prominently displayed and messages included a time stamp that indicated the earliest time a response could be received (Figure 6.4).


Crewmembers' Mean Criticality Ratings of Individual Protocol Elements and Conventions



HERA (Trained)

Repeat addressee (voice)

3.75 (1.26)



Include time (voice)




Provide topic

4.75 (0.50)

4.88 (0.35)

4.63 (0.52)

Acknowledge communications

4.00 (0.82)

4.25 (0.89)


Push information

3.25 (0.50)


4.63 (0.74)

Chunk information

3.50 (0.56)

3.33 (0.58)

4.25 (0.71)

Repeat critical Info (voice)

4.25 (0.50)


4.50 (0.76)

Type critical info in caps (text)

2.50 (0.56)



Note earliest time to expect response


3.75 (1.23)

4.25 (0.71)

Use log to track related messages

4.75 (0.50)

4.75 (0.50)


Announce complex or critical messages


4.25 (0.96)

4.75 (0.46)

Postpone non time-critical message to wait for critical info

4.00 (0.82)

3.50 (0.58)


Notes: Standard deviations are in parentheses. Maximum rating was 5. NEEMO-19 crew used text communication only.

Text communication in NEEMO-19 with tool indicating earliest time to expect response to message

FIGURE 6.4 Text communication in NEEMO-19 with tool indicating earliest time to expect response to message.

Overall findings suggest that the communication protocol approach holds promise for helping space crewmembers and MCC communicate and collaborate effectively and successfully even when their communication is delayed. In reflecting on his experience with living in Aquarius and working under communication delay, Randy Bresnik, the commander in NEEMO-19 writes:

This past week of living aboard Aquarius as saturated divers has been filled with awe and wonder. The majesty of this beautiful undersea world was a beauty to behold. The dangers are self-evident and ever present, but so were the amazing opportunities to train in such a unique and hostile environment. Overcoming these challenges made the results of our work seem all that more rewarding. Evaluating equipment, developing procedures, and researching operations in an environment with a delay in communications was our mission. Thanks to the hard work and dedication of the entire team of NEEMO 19, we were wildly successful.

The critical element evaluated during the mission was the element of time.

A 10 minute round-trip communications delay was implemented to determine how operations between Spacewalking crew and MCC could function. This has a direct application to possible future human exploration of other planets or asteroids. (Bresnik. 2014)

Based on our research in NEEMO and HERA we strengthened the communication training. We added examples that illustrate how easy it is for remote team members to misapply well-rehearsed habits of synchronous communication to asynchronous conditions, and used these examples to emphasize the importance of protocol elements that NEEMO and HERA crews undervalued. We also converted the communication training into a stand-alone training module that can be used to prepare crewmembers and flight controllers for the challenges of communication delay.

Notably, the communication protocols not only target how to speak or write during asynchronous conditions, but also point to technological solutions. In fact, some technological changes have already been implemented in response to our early findings. One example is the text tool that was adopted in NEEMO-19 and assisted the crew with the temporal aspects of communication. Further improvements might be a less chat- and more email-like text tool that includes a subject header and establishes links between related messages to make it easier for conversational partners to follow a conversational thread. A text tool could also provide a template that gives structure to a message and highlights its components. Likewise, voice communication could be facilitated if recordings of messages were available to both sender and receiver, and if the recordings indicated when a message was transmitted. And lastly, it is conceivable that the recording tool would include prompts for specific message components (e.g., This message is in regard to.... The time is....). Ultimately, technological implementation of protocol elements can reduce cognitive workload for both the crew and MCC, and can provide viable communication support for long-duration exploration missions.

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